Australia Ventilaiton Workshop 2014
Getting chicks off to a good start
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Brooding Temperature
and Bird Performance
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Brooding temperature
Air quality
Litter quality
Feed
Water
Light intensity
Brian Fairchild
The University of Georgia
Why is house temperature so important?
Cold weather

In cold weather what are the two first things typically
considered to reduce fuel costs?
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Dependent on environmental
temperature to maintain body
temperature
As air temperature decreases, body
temperature will decrease
Chicks are extremely easily to chill in the first
few days
Onset of thermoregulation
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Thermoregulation
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Run heaters less
Do not exhaust the hot air
Chicks body temperature
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Insulation – feathers
Body mass
Lowers body mass to surface area ratio
Increase in thyroid function
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T3
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Australia Ventilaiton Workshop 2014
When is broiler feed conversion most efficient?
Feed energy distribution
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Growth
Maintenance
If Birds are not exposed to stressors
Why is house temperature so important?
Advances in broiler growth
ACRBC (1957) with 2001 diet
Ross 308 (2001) with 2001 diet
Day 43
Day 57
Day 71
Day85
Havenstein et al., 2003
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When body temperature drops
Temperature sensitivity
Chicks spend more time huddling
Immune system impaired
Digestive system less efficient
Increases breakdown of
carbohydrate and lipid reserves
Impairs growth
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Broiler housing has to by dynamic
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Young chicks are sensitive to cold
Older birds are sensitive to heat
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Australia Ventilaiton Workshop 2014
Performance
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Thermal comfort zone & performance
Optimum performance can not be achieved if the
proper brooding temperature can not be maintained.
Chicks will find their comfort zone
Whether it be closer to the brooder
105.0°F
105
100
95
90.5
90
105.5
85
80.0°F
Cool and drafty conditions
ceiling: 28.0
Or further away
45.0°C
40
30
floor: 15.3
20
10
floor: 29.1
10.0°C
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Australia Ventilaiton Workshop 2014
What is meant by brooding temperature?
Brooding temperatures
40.0°C
40
35
31.7
30
26.9
25
20
18.0°C
Air temperature? or Floor temperature?
Brooding temperatures
Performance When
Temperatures are Too Low?
Brief cold exposure
Exposure to
65oF
Long term effects of cold temperature
(18.3oC)
for 2 hours

Chicks exposed to 55oF (12.8oC) for 45 minutes were
compared to chicks at normal brooding temperatures.
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Birds were grown at normal temps for the remainder of
the grow-out
Body Temperature (C)
39
38
37
65 F
36
95 F
35
34
24
48
72
96
Hours
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Australia Ventilaiton Workshop 2014
Effects of 45 minute cold exposure
Brooding Temperature Study
Two Temperatures
Low 0-5 d=79oF (26.6oC)
Low 6-12 d=76oF (25oC)
High 0-5 d=90oF (32oC)
High 6-12 d=85oF (30oC)
1.40
1.35
1.30
1.25
1.20
Normal
Cold Stressed
250
12d Body Weight Gain (g)
Body Weight @ 35 Days of Age
(Kg)
1.45
Treatment
248
246
244
242
240
238
236
Low
High
Treatment
Bruzual and Brake, 2000
Brooding at 80oF (27oC) vs 90oF(32oC)
(weight at 10 days)
Brooding at 80oF(27oC) vs 90oF (32oC)
(feed conversion at 12 days)
1.6
120
1.4
Feed Conversion
Weight (g)
100
80
60
40
1.2
1.0
0.8
0.6
0.4
20
0.2
0.0
0
80 F (27 C)
80 F (27 C)
90 F (32 C)
90 F (32 C)
Bruzual and Brake, 2000
Brooding temperature and mortality
Bruzual and Brake, 2000
Brooding at 80oF (27oC) vs 90oF (32oC)
(signs of ascites at 10 days)
12
2.5%
10
Ascites (%)
Mortality (%)
2.0%
1.5%
1.0%
0.5%
8
6
4
2
0.0%
80 F (27 C)
90 F (32 C)
Brooding Temperature
Bruzual and Brake, 2000
0
80 F (27 C)
90 F (32 C)
Brooding Temperature
Bruzual and Brake, 2000
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Australia Ventilaiton Workshop 2014
Optimum brooding temperatures?
Birds never catch up
35 d Body Weight (Kg)
1.45
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High gas prices in the 70’s many people lowered brooding
temperatures
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Later work implicated low brooding temps in ascites
1.40
1.35
1.30
1.25
1.20
Cold Stressed
Control
Treatment
Bruzual and Brake, 2000
Body weights (21 d)
Brooding temperature study
804
Treatments
Week 1
95oF (35.0oC)
90oF (32.2oC)
85oF (29.4oC)
80oF (26.7oC)
802
Week 2
90oF (32.2oC)
85oF (29.4oC)
80oF (26.7oC)
75oF (23.9oC)
Week 3
85oF (29.4oC)
80oF (26.7oC)
75oF (23.9oC)
70oF (21.1oC)
800
798
Body Weight (g)

796
794
792
790
788
786
35-32-29
32-29-27
29-26-24
Temperature (Weeks 1-3)
Deaton et al., 1996
Deaton et al., 1996
Mortality and ascites (42 d)
Feed conversion (21 d)
Total
1.4
1.3
1.2
1.1
35-32-29
32-29-27
29-26-24
26-24-21
Temperatures (Weeks 1-3)
Mortality/Ascites (%)
Feed Conversion
1.5
4
3
2
1
0
35-32-29
Deaton et al., 1996
Ascites
5
32-29-27
29-26-24
Temperatures (Weeks 1-3)
26-24-21
Deaton et al., 1996
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Australia Ventilaiton Workshop 2014
What affects chick body temperature
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Air temperature
Floor temperature
Feed consumption
Bird density
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And
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Target temperatures
Relative humidity (RH)
104oF (40oC)
Target temperature/Rh
Temperature
30oC
3
28oC
6
9
27oC
26oC
12
25oC
15
24oC
18
21
23oC
22oC
24
21oC
27
20oC
Human heat loss
Age
Temperature
Rh
Day old
30oC
50 – 70% Rh
3
6
28oC
27oC
50 – 70% Rh
50 – 70% Rh
9
26oC
50 – 70% Rh
12
25oC
50 – 70% Rh
15
24oC
50 – 70% Rh
18
21
23oC
22oC
50 – 70% Rh
50 – 70% Rh
24
21oC
50 – 70% Rh
27
20oC
50 – 70% Rh
Poultry heat loss
28%
air
evaporation
72%
How Rh affects effective temperature
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40%
60%
Age
Day old
For a 2.2 Kg broiler (at 25oC) increasing the relative
humidity from 50 to 70% feels roughly the same as
increasing the air temperature 5oC (30oC).
air
evaporation
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Australia Ventilaiton Workshop 2014
Humidity is equally important to birds
Effective temperature for day-old chicks
Is 30oC, 60% Rh = 30oC, 20% Rh?
Target temperature as a function of Rh
Target temperature as a function of Rh
Age Temperature
Age Temperature
Dry Bulb Temperature at Rh%
40%
50%
60%
70%
80%
Dry Bulb Temperature at Rh%
50%
60%
70%
1
30oC
36
33.2
30.8
29.2
27
1
30oC
36
33.2
30.8
29.2
27
3
28oC
33.7
31.2
28.8
27.3
26
3
28oC
33.7
31.2
28.8
27.3
26
6
27oC
32.5
29.9
27.7
26
24
6
27oC
32.5
29.9
27.7
26
24
9
26oC
31.3
28.6
26.7
25
23
9
26oC
31.3
28.6
26.7
25
23
12
25oC
30.2
27.8
25.7
24
23
12
25oC
30.2
27.8
25.7
24
23
Relative humidity & body temperature
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At hatch the chick environment is
Temperature 95oF (35oC)
RH
80 %
40%
80%
Relative humidity and body temperature
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Poultry House Brooding
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Effective Temperature
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Temperature 90oF (32oC)
RH
25%
Chicks will be colder
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Australia Ventilaiton Workshop 2014
Chilled chick symptoms
Factors that affect broiler chick temperature
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Floor moisture content
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Damp or wet bedding material will chill chicks
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Brooding temperature
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Low brooding
temperatures
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Pile under brooders
Huddle in feeder pans and trays
Increased mortality
Reduced growth rates
Poor uniformity
Increased incidence of Ascites
Fecal droppings wet
Pasty vents
Low brooding temperatures = problems later
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Metabolic Disorders
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Less movement
Reduce body weight gains
Increased feed
consumption
Poor feed conversion
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Bacterial Diseases
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Four house farm
Houses ~ 14 years old
Renovated
Foam used to totally
enclose one house
(Foam insulation)
Gangrenous Dermatitis
E. Coli
Salmonella
I.P
Good environment = less stress
18
16
14
Mortality (%)
UGA field study
Ascites
Sudden Death Syndrome
(flip over)
Leg problems
12
10
8
6
4
2
0
Flock 1
Flock 2
House #1
Flock 3
House #2
House #3
Flock 4
Flock 5
House #4
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Australia Ventilaiton Workshop 2014
Keeping birds warm with propane & feed
What is the correct temperature?
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Watch the birds and let their behavior guide you
Summary
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Birds more sensitive to relative humidity
Floor temperature during brooding important
Proper house temperature is key to getting full genetic
potential from broilers
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Critical to good feed conversion
poultryventilation.com
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