Table Of ContentAbout the authors L Improving your results and animal welfare
A
Y In theory we all know more or less what to do. But not every
Monique Bestman studied biology at Wageningen University, E chicken farmer puts this theoretical knowledge into practice. So
R
Layer Signals doesn’t just devote space to the latest insights, but
with a particular focus on animal behaviour. She has worked
also focuses on how to turn knowledge into effective action.
for the Louis Bolk Institute for 10 years conducting research ‘Laying hens are not egg laying machines. LAYER S
I By consciously examining signals and analysing them you can
into the health and welfare of layers. She frequently visits G
SIGNALS optimise your operational management step by step.
Proper care requires knowledge of the animal
poultry farms, has written various publications for poultry N
farmers and contributes to national and international study A practical guide A Steps aimed at improving management:
and the capability to use this in practice.
groups and conferences. In the past few years she has devoted to layer focused L 1. What am I seeing?
management S
a lot of attention to rearing as, according to Monique, ‘What is For optimal results.’ 2. Why is this happening?
3. Should I leave it or should I take action?
learned in the cradle is carried to the grave, a fact that is often A
4. How do I solve the problem now?
underestimated’. p
r 5. How can I prevent the problem happening again in the future?
Not all poultry farmers maximise the full potential of their birds. Both kept in cage a
c 6. Bring about actual change.
t
Marko Ruis studied biology and has been employed as a or floor systems, for a good performance during the production period, the manage- ic t 7. See whether this has the desired effect, and if not start again
researcher at Wageningen University and Research Centre ment should be correct and efficient. But how do you know that what you are doing al h at step 1.
g
since 1994. He gained his PhD through research into fatten- is right? Your chickens continuously send out signals: about their health, how well u
i g
ers. His sphere of research is the health, welfare and behavior they know their way around their surroundings and whether they feel happy and de d By consciously running through these steps each time, you will
of poultry and pigs. Marko considers knowledge transfer to comfortable. to i improve your operating results and, more importantly, the welfare
livestock farmers and ‘green’ education to be of the utmost la r e of your animals.
importance. ‘There is knowledge in abundance, but it is often Do you recognise the signals your chickens are giving? Do you know the difference ye y For healthy and happy chickens are to your advantage too!
r t
not widely available or easy to understand. A researcher knows between abnormal, runny droppings and healthy caecal droppings? Are you able to fo p c
how to track down the knowledge, which then has to be tai- identify abnormalities of the egg and trace this back to the cause? And do something cu
lored to fit’. about it? se o e
d
m
c t
Jos Heijmans works as a veterinarian specialised in poultry If you recognise the signs that point to potential prob- a
n LAYER o
health at the Animal Health Service (GD). He has also been a lems, then make sure you are armed with information ag
part time guest lecturer at the Faculty of Veterinary Medicine to take the appropriate steps to get your flock back on em rSIGNALS
in Utrecht since 2003. Poultry still fascinates him, even after track. But to do so, you must know all the ins and outs of e p
n
23 years. Communicating information is an important part your own farm and be able to assess the impact these t
of his tasks at the GD: ‘Combining my passion for language changes will have on your animals.
with my wide experience in poultry health has enabled me to
A PRACTICAL GUIDE TO LAYER FOCUSED MANAGEMENT
make many contributions to articles and poultry trade journals. Layer Signals is a practical guide that shows you how
Translating scientific insights into practical application is cen- to pick up the signals given by your animals at an early
tral here.’ stage, how to interpret them and which action to take.
Koos van Middelkoop has a wealth of experience in the poul-
Poultry Signals® presents practical knowledge of animal-
try sector, in theory and in practice. After starting his career oriented poultry farming in an easy, accessible format.
at Het Spelderholt Institute, he was employed as a geneticist
in the commercial sector for 13 years before returning to the
arena of research at the Animal Sciences Group. Since 2003,
he has worked as an independent advisor. ‘The differences
between animals, and the hereditary aspects in particular, still
intrigue me. In my approach I always take the animal as my
starting point.’ He currently works all over the world.
www.roodbont.com www.louisbolk.nl www.gddeventer.com www.livestockresearch.wur.nl
Cover_Layer_Signals_UK_12mmRug.indd 1 13-11-13 16:04
Credits
Layer Signals (14, 93, 95, 96, 97), Pas Reform (45, 46,
47, 51, 91, 93, 99), PTC+, Helmich van
Authors original edition Rees (7, 32, 33, 45, 52, 62, 79, 96, 98),
Rob van Veldhuizen (103), Ron Jöerissen
Poultry Signals Roodbont Publishers B.V.
(55), Schippers BVBA (109), Silly Chick
Monique Bestman P.O. Box 4103
(26), Tine Jansen (46), Ton van Schie (94),
Marko Ruis 7200 BC Zutphen
Twinpack (98), Vencomatic (5, 6, 7, 9, 12,
Jos Heijmans 15, 16, 24, 25, 26, 29, 31, 39, 43, 57, The Netherlands
Koos van Middelkoop 94), Verbeek (104), Wayne Skews, poultry- T +31 (0)575 54 56 88
farming.co.za (114), Wouter Steenhuisen E info@roodbont.com
Content Editors Poultry Signals, (46, 91, 91, 96, 109), Zonne-Ei-Farm B.V I www.roodbont.com
edition Layer Signals (5).
Wouter Steenhuisen
Theo Peters Illustrations
Phill te Winkel Marinette Hoogendoorn
Koos van Middelkoop
Design
t
Final editing Dick Rietveld, Erik de Bruin, Varwig Louis Blok Instituut
h
Ton van Schie Design www.louisbolk.org
English Translation Advisor g
Agrolingua Jan Hulsen, Vetvice Groep d
i
Photography Special thanksr to: e
Photography Cover Peter vayn Agt, Marleen Boerjan, Livestock Research Wageningen UR
Front: Marcel Bekken (t), ASG (b) Pieter Bouw, Mijndert van den Brtink, www.livestockresearch.wur.nl
Front flap: LBI Hilpko Ellen, Rick van Emous,c Marrit
Back: ASG van Engen, Teun Fabri, Thea Fiks,
Back flap: LBI , ASG, GD, Koos van oNiels Geraerts, Arjan Geussinklo, Jan
Middelkoop van Harn, Wim Hoeve, Jan Hulsen,
Ron Jöerissen, Ingrid de Jong, René
c t
Photography Interior: Kieftenbelt, Gerjan Klok, Cécile GD Deventer
o
Alpharma (116), Andries de Vries (15, 16), Korevaar, Marinus van Krimpen, www.gddeventer.com
Arthur Slaats (28, 48), ASG (10, 16, 18, Pieter Kruit, Jan en Marcel Kuijpers,
24, 25, 26, 27, 29, 31, 35, 36, 38, 38, Ferry Lerenstra, Sander Lourens, Jac
40, 41, 49, 54, 69, 73, 75, 75, 76, 80, Matipjsen, Monique Mul, Bert van This publication has been made possible with
81, 85, 87, 88, 91, 92, 93, 95, 96, 100,
Nijhuis, Kees van Ooijen, Wim Peters, the support of the Dutch province Gelderland.
102, 103, 104, 107, 109, 118, 119),
Dr. David Pollock, Bianca Reindsen,
AviVet: Roland Bronneberg (92), Back
Berry Reuvekamp, Henk Rodenboog,
yard farming (50), Bastiaan Meerburg
(103), BiotechMichael (61), Bloemendaal Jorine Rommers, Piet Simons, Arthur © Roodbont Publishers B.V., 2013
Eierhandel (94), C. Bennet(47), Christel Slaats, Alex Spieker, André van
Lubbers (98), Edward Mailyan (91), GD Straaten, Otto van Tuil, Cor van de Layer Signals is part of the Poultry Signals©
(57, 28, 50, 60, 64, 83, 89, 91, 92, 101, Ven, Jan-Paul Wagenaar, Ruud van book series.
105, 106, 107, 108, 108, 110, 111, Wee, Sible Westendorp, Helmich van
112, 113, 114, 115, 116, 117, 118, 63),
Rees, Laura Star, Joost Koster, Jeroen The authors and publisher have compiled this
GULLI.ver (15), Henk Heidekamp (53),
Henk Rodenboog (50), Hilly Speelman van der Heijden, Paul Buisman, Henry publication with the greatest care and to the
(42), Interbroed leghennen (66, 67, 80), Arts, Gerd de Lange, Merel van der best of our knowledge. However, the authors
internet (98), Jansen Poultry Equipment Werf, Mari van Gruijthuijzen, Richard and publisher do not accept any liability due
(24), Koos van Middelkoop (6, 10, 15, 16, Wentzel, Andries de Vries, Jacco to damage of any kind resulting from actions
32, 33, 47, 50, 51, 69, 70, 71, 72, 79, Wagelaar, Jan Dirk van der Klis and and/or decisions based on this information.
88, 89, 90, 91, 93, 95), LBI (4, 6, 8, 9, Karin Jonkers. No part of this publication may be dupli-
17, 18, 22, 25, 28, 29, 32, 42, 43, 44, 46,
cated, photocopied, reprinted or reproduced
48, 56, 58, 60, 68, 74, 75, 78, 84, 86, 87,
in any way without prior written permission
90, 98, 101, 108), Marcel Berendsen (8,
from the publisher.
9, 11, 14, 25, 26, 30, 31, 33, 40, 48, 49,
51, 54, 55, 57, 58, 60, 62, 63, 64, 64, 73,
75, 76, 77, 86, 92, 93, 100, 107), Moba ISBN 978-90-8740-124-5
2 Layer Signals
Contents Introduction 4
1 Seeing more by looking more closely 8 4 Laying hens 72
Picking up the signals 9 Schedules aren’t written in stone 72
Using the signals 10 Moving in 73
Farm records show objective signals 12 The ideal curves 74
Analysis criteria for egg production 14 Gear management towards nesting peak 75
Inspection outside the house 15 Feed selection 76
Inspection in the poultry house 16 Feed and light 77
Paying attention to the hen 17 Deficiency signals: eating feathers 78
Bird behaviour 18 Feeding when temperature is low 78
Anatomy 20 Feeding when temperature is high 79
Respiratory system 22 Drinking 81
Senses 23 Water output from the nipples 82
Checking individual birds 24 A second laying period? 84
First impressions 25 Pecking, feather pecking and cannibalism? 84
A closer look 26 Di fficult to reverse 85
Signals from manure 29 tFeather pecking 86
Cannibalism 87
h
2 The hen and her environment 30
Differences between husbandry systems 31 5 egg signals 88
g
Open sided or closed poultry houses? 32 A fresh egg? 89
d
Climate management in high temperatures 33 Internal egg quality 90
i
Ventilation 34 Shell abnormalities caused before laying 91
r e
Assessing ventilation in the poultry house 35 Finding abnormal eggs 92
Climate under control y 36 Shell abnormalities caused after laying 93
Effective temperature (wind chill factor) 37 Ctracks and breaks 94
Air p 38 cQuality report from the egg wholesaler 97
Light 39 Egg production problems 98
Dust o 4e0
Why free-range? 42 6 health 100
Covered rangce or winter garden t43 Disease signals 101
o Biosecurity outside the house 102
3 rearing hens 44 Biosecurity in the house 103
A good start is half the battle 45 What seems to be the trouble? 104
r
The early days 46 Gastrointestinal problems 105
p
Quality of day-old chicks 47 Respiratory diseases 106
Comfort signals in day-old chicks 48 Disorders in the locomotive organs 108
Temperature 49 Sudden increase in mortality 109
Weak chicks 50 Summary of the main diseases 110
Cage rearing 51 Viruses 110
Floor rearing 52 Bacteria 113
From 6-15 weeks 53 Internal parasites 115
Weight and condition 54 Coccidiosis 116
Development of feathering 55 Worms 117
Training good behaviour in aviaries 56 Red mites 118
From rearing to laying: 16-25 weeks 57
Light 58 Index 120
Light during rearing 59
Moving from rearing to laying house 60
Vaccinations 61
The right way to vaccinate 62
Good vaccination - a science in itself 64
Keep the use of antibiotics to a minimum 65
From small to adult in 18 weeks 66
Feather pecking during rearing 68
Beak trimming 69
Methods of beak trimming 70
Contents 3
ChApTer 2
The hen and her environment
t
h
g
d
i
r e
y
t
p c
o e
Cage or floor: there is a world of difference between the two. With caged chickens, Good management
requires thinking about
the birds have no choices acnd it’s mainly the farmter who calls the shots. In floor things from the hen’s
o point of view and
systems the hens can decide for themselves where to walk, lay their eggs or drops
looking out for them
their faeces. As a poultry farmer you must bear this in mind and respond accord- properly.
r
ingly. You can influence their behaviourp with food, water, light and other factors.
There are also great differences within cage and coming and going. A healthy accommodation nat-
floor systems. In traditional cages the chicken can’t urally also includes the right temperature and the
do very much, but in bigger systems containing right amount of light, air, food and water.
more than 40-50 hens, you need to take the birds’
behaviour into account. In floor systems it makes a
big difference whether the birds are free-range or the
poultry house is fitted with a type of aviary system.
In the latter case in particular, you will definitely
need to take the birds’ behaviour into account.
The hen prefers her living environment to be
designed in such a way that there is a separate
area for each activity: resting, laying eggs, scratch-
ing, eating and drinking, dust bathing. For resting,
laying eggs and dust bathing she needs quiet places
These perches are at the top of the house where there
where she won’t be disturbed by other chickens
are no other facilities. The resting chickens are not dis-
turbed there, so they can get real peace and quiet. In
cage systems there is very little room for birds to be able
to rest undisturbed.
30 Layer Signals
Differences between husbandry systems There is also a risk of egg loss because hens can
There are various types of husbandry systems irre- lay their eggs outside the nest. Avoiding floor eggs
spective of the climatic conditions. In most coun- requires a lot of attention and work, particularly in
tries hens are kept in small cages. In countries the early morning. In case of floor eggs start walk-
where these are banned, mini-aviaries or enriched ing through the hen house at about the time they
cage systems may be a permitted alternative. lay their eggs, disturbing the hens that try to lay
In floor housing chickens have much more room their eggs outside the nests. The choice of hous-
to move and are more free to exercise their natural ing systems depends not only on local cost levels
behaviour. But in doing so they use more energy but also on society’s demands in terms of animal
and therefore eat about 5 grams more feed a day. welfare (laid down in law). And the choice must of
course suit the poultry farmer and his staff.
Cage system Floor system
+ Most efficient method of poultry-keeping – When something goe s wrong the consequences are more serious
– Birds are limited in their natural behaviour – Higher managemtent level necessary: behaviour is an extra factor to
(animal welfare) take into accohunt
+ Less labour-intensive + Birds can display their natural behaviour
+ Better hygiene (diseases spread more slowly) + Better image (meeting demands of society)
+ Climate easier to control – More lagbour-intensive: a lot of extra work in the poultry house
+/– Ventilation systems work differentldy in floor systems (fewer chickens
so less heat generated, susceptible to weather influences, reduced
i
pressure ventilation not possible in free-range system)
r e
y
t
Meeting the birds’
p c
behaviour in cages
Enriched caged systems also o e
feature elements that allow birds
to demonstrate limited natural
behaviour, like mats for their c t
nails or flaps that give them o
some privacy.
r
p
With caged systems there are several
options, from very small cages (5 hens
per cage) (picture right) to cages con-
taining 30 or more birds (picture top).
Infections spread faster in a house with non-caged
chickens than in a caged system because the chickens
spread the germs all over the house and come into con-
tact with other chickens’ manure.
Chapter 2: The hen and her environment 31
Open sided or closed poultry houses? Rearing
In open sided poultry houses there is often little In open poultry houses or houses that allow a lot
that can be done about the temperature around the of light, the day length can’t be shortened and you
birds. But it is possible to place fans by the birds to have to deal with the natural day length. Getting
cool them down. Curtains are often used to prevent the birds into lay at the required time may be a
the house from getting too cold at night. problem, particularly during rearing. A modified
If the temperature gets very high or low, the feed, lighting scheme may help.
the amount of feed and the feeding time will need
to be adjusted accordingly.
t
h
g
d
i
r e
y
t
p c
In open houses climate control and lighting coosts are limited, but so is your e
control over them. In many countries birds are housed in open poultry hous-
es. The light can’t be dimmed.
c t
o
r
p
In closed houses the climatic aspects can be regulated,
so you are in better control of your production. But a reli-
able power supply is essential and the costs of housing
and climate control are high.
You can restrict the influx of direct sunlight with a roof that extends well
beyond the edge of the building. When building a new poultry house, make
sure the length of the house runs east-west. This is another way to restrict
light influx at noon.
32 Layer Signals
Climate management in If it gets warmer or too
warm, in floor housing you
high temperatures
will notice that the birds are
The optimum house temperature for laying hens dust bathing more, ruffling
is about 25°C. Up to a temperature of about 30°C their feathers and spreading
their wings. Birds in a cage
you will notice that the hen can still regulate her
system are not able to do
own temperature reasonably well. Above that you this, but they pant with their
will need to provide cooling. A desert cooler can beaks open and spread out
their wings. It is important
lower the indoor temperature quite significantly
to make sure that every bird
when the outside air is hot and dry. Make sure the in every cage has the best
incoming cooled air is not directed straight onto possible ventilation.
the birds.
If there is no cooling facility, ventilation can help
prevent heat stress.
Chickens cool themselves down by evaporating
moisture by panting. When chickens pant, the air
around the head contains high levels of moisture. t
It is important to get rid of this air as quickly as h
possible so that more moist air can be given off.
g
A few extra fans that provide more air movement
d
and are directed at the birds are an effective way
i
of dealing with high temperatures. You should see
r e
the feathers moving in the airflow. As they can’t
y
sweat, excessive cooling won’t affect the birds as
t
long as the air temperature is higher than 26°C. p c
o e
c t
o
r
p
In intensive sunshine the roof of the poultry house can
get very hot and the incoming air around the house can
heat up to quite a high level. Spraying the roof creates
a lot of condensation which cools it down. Atomisers
installed under the roof of the house can also provide
some cooling through humidification. But only when the
These windows can be opened, but they can cause
relative humidity is not too high.
draughts and can only be open or closed. There is little
control.
provision for cool nights
In tropical regions the outside temperature can often drop
well below 25°C at night, and even to around freezing point.
In open sided poultry houses you will therefore need to close
the curtains at night. In this photo you can see that these
curtains can be pulled up. The cold air flow should not be
directed at the birds. Birds in a strong current of air below
25°C can suffer from problems with colds (mucous) and
sometimes coryza. In mechanically ventilated poultry houses,
air inlets should be designed in such a way that the incoming
air is directed to the ridge of the house where it will be mixed
with the warm indoor air.
Chapter 2: The hen and her environment 33
Ventilation Mechanical ventilation:
The house climate is determined by the combi- Even in areas where natural ventilation can work
nation of ventilation, heating and cooling. The well, farmers are increasingly using mechanical
choice of the ventilation system should be suited ventilation. The investment and energy use are
to external conditions. Simple or complex, the sys- higher, but it offers more control options and thus
tem needs to be managed. And even with a fully it is more likely to have good results. The air is
automatic system your own perception remains expelled by ventilators: the key word is underpres-
crucial (ears, eyes, nose and skin). sure. The slight negative pressure in the house
pulls air in via all openings at a similar rate. It is
Natural ventilation therefore important that there are no openings
Natural ventilation doesn’t make use of fans for besides the air inlet valves: they could disrupt the
incoming or outgoing air. The fresh air enters the entire system!
house via open inlets, often fitted with controlled
valves, panels or curtains. And leaves through the
same openings and/or the roof. Natural ventilation
is often seen as a simple and inexpensive system. t
Whether that is true depends on the results that h
can be achieved from such a poultry house.
g
d
Cross ventilation: The air is expelled on one side of the house
iand fresh air enters through inlets on the opposite side. This system
r allows small, but aleso large quantities of air to move.
y
t
p c
Longitudinal ventilation: The air intake valves are on the both
o e
sides of the house. The fans are placed in the rear wall. This system
does especially well in those areas where the temperature differ-
c tences are not too large (such as a maritime climate). Investment and
operating costs are relatively low.
o
r
Roof ventilation: The fans are installed in ventilation ducts in the
p roof. The air intake valves are evenly distributed over the two sides
of the house. This is often used for minimum ventilation in colder cli-
mates. Small quantities of air can be well managed. For larger quanti-
ties of air, the system is often more expensive because of the large
number of fans and air ducts that are required.
Tunnel ventilation: The fans are placed in the back wall and air
is sucked in through air inlets in the front wall of the house (or in
the final few metres of the side walls at the front end). This creates
relatively high air velocity. This high air velocity (up to 3.4 m/s) gives
a cooling effect on the animals (chilling effect). This system is used
when large quantities of air are required.
Combinations: Tunnel ventilation is often used in combination with
a roof or longitudinal ventilation, for example. In that case, the roof/
longitudinal ventilation is used for minimum ventilation. When more
is required these valves are closed and the tunnel inlets opened. An
increasingly used concept.
34 Layer Signals
Assessing ventilation in the poultry house
Avoid ventilation errors.
In floor housing systems, the distribution of birds Check all your equip-
ment at set times.
over the house tells you something about the qual-
ity of ventilation. But you can also assess the venti-
lation in other ways.
Enter the house with bare, wet arms or wearing
shorts, go and stand in the parts of the house
where there are too few chicks and feel whether
there is a draught there. Check whether the lit-
ter feels cold. See whether there is a pattern in
the way the birds are distributed throughout the
Good ventilation
house and whether this has anything to do with
the position of the lamps, fans, air inlet etc. If you
change the settings, give the chicks a couple of
hours to adjust. Don’t conclude too quickly that
the change has not worked or is no good. Make a t
note of what you have changed. h
g
d
i
poor ventilation with floor rearing r e
If you cannot feel it yourself, do a smoke test to see howy quickly the air is flowing through the
house. You don’t have to take the chicks out of the house to do this. There are several options:
t
p c
o e
c t
o
r
● The fresh, cold air in the middle sinks and ● The fresh, cold air sinks too quickly and is
p
there is little air movement at the sides. therefore not being heated up enough.
● The chicks avoid the middle and go to the The chicks keep to the outermost quarters
sides of the house, resulting in damp litter. and the middle of the house.
● Reduce the underpressure. ● This has created two empty strips down the
length of the house: a zebra crossing effect.
● Increase the underpressure.
● The chicks move away from the edges and are ● In hot weather the flaps will turn.
mainly in the middle. ● The air will pass right over the chicks at
● The flaps are too tightly shut so there is too little high velocity.
air entering through each flap which dissipates ● This will make the air feel quite cool near
too quickly. the birds (wind chill effect). This should only
● Open some of the flaps about two fingers more. be done deliberately if the ambient tem-
perature is very high.
Source: Henk Rodenboog
Chapter 2: The hen and her environment 35
Climate under control
The climate in a house is a combination of tempera-
ture, air velocity, indoor air composition, dust and
light. And very important: the (micro) climate around
the birds is what counts! These factors can impact on
one another. Get a climate expert to check both the
climate computer and the climate once or preferably
twice per year. The expert works with these systems
every day and knows what the best setting should be.
Sometimes it will be different from the manufacturer’s
recommended setting. The expert can also pick up When setting the house temperature, take the qual-
on changes in the sensors which could indicate that ity of the feather cover into account. A featherless hen
needs a higher temperature and is more susceptible to
the climate is no longer being optimally controlled.
draughts and air flows.
Naturally you should also be alert to signals that
indicate whether or not the climate is right. Chickens
might avoid certain places or huddle together, for t
example, or there may be a stuffy smell. You get used h
to bad air quite quickly, so go with the impression you In de onderste verdieping van de stal is te weinig ruimte
voor de lucht tussen de verdiepingsvloer en de boven-
g
get when you enter and leave the house. kant van de stellingen.
d
i
Air flows r e
Wrong y right
t
p c
o e
c t
o
r
In de onderste verdieping van de stal is te wpeinig ruimte In de onderste verdieping van de stal is voldoende
Bad air circuvolaotri odne lcuacnht otucscsuern idne h voeurdsieepsi nwgisthvl oliettrl een v doelu bmovee an-nd a There is pruliemnttey v ooof rr doeo mluc hatb tousvsee nt hdee vtieerrdsie tpoin gasllvolowe rt ehne d aei r right
relatively larkgaen tn vuamn bdee rs otefl lionbgesnta.cles. Air does not circulate properly into the mboidvednleka ontf vtahne d heo sutesllein.g Iet ni.s also less likely that there will
in aviary houses that are too low. There are also places with no air be places without air movement. You can also direct air to
movement in the middle of the poultry house. the middle of the house with pipes or ducts from outside run-
ning along the ceiling to the middle.
LLOOOOKK--TThhIINNKK--AACCTT
What is wrong with this
temperature sensor?
This temperature sensor is level with the top perch. That’s too high. For accurate
temperature measurement, it is important that the temperature sensors register the
In de onderste verdieping van de stal is voltdeomenpdeer ature where the chickens are. So it must be in among the chickens, but not in
ruimte voor de lucht tussen de verdiepingsval opeor senit ioden where the chickens can sit against it. Check regularly that the temperature
bovenkant van de stellingen. sensors are working properly by hanging a good manual thermometer next to them.
36 Layer Signals
