Chick body temperature: from hatchery to farm

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At hatch time of chicks, there are three physiological systems that are not fully developed:

• Digestive
• Immune
• Temperature regulation

In this article we will talk about temperature regulation

Upon hatching, the birds are poikilothermic animals: their body temperature will rise or fall depending on the outside temperature, requiring a metabolic effort by the birds. It will take around 4 days for chicks from adult flocks and 5 to 6 days for birds from young flocks for the thermoregulatory system to behave homeothermically – constant body temperature.

There is a range of body temperature known as the comfort zone, where the birds are comfortable with the temperature that surrounds them: The best way to “find” the comfort zone is to measure the birds’ cloacal temperature. If the cloacal temperature is above or below this range, adjustments should be made to the ambient temperature.

This information will help us adjust the temperature and ventilation of the hatcher according to the flock of birds that are currently inside the machine.

During sexing, vaccination or in beak or spur treatments, the temperature of the birds will drop to ranges of 38.3 – 38.9 ºC (101-102 ° F).

Particular care should be taken with birds after being exposed to spray vaccines, as their temperature can drop greatly if the drop is not correct. At the end of these operations, in the waiting room to be loaded in the truck, the birds must recover their body temperature between 39.5 – 40.5 ºC (103-105 ° F).

Upon arrival at your farm’s destination, as the birds are being lowered from the truck, the temperature of the birds inside the boxes should be monitored.

Preferably, the temperature of birds from different parts of the truck should be monitored, particularly when it is a large truck.

In addition to the correct air temperature of the house, it is important that the floor is acclimatized before the birds arrive. The photo shows how the birds are distributed in a receiving ring depending on the soil temperature.

Note: not only the low temperature but also the high temperature will make the birds not look for food and water. They will survive two or three days because of the nutrients they have in the yolk sac, but they will eventually die. If the birds decide not to drink and eat as a result of a very adverse environmental situation, necropsy will show signs of:

• Emaciation and dehydration, kidney inflammation
• Ureters distended with urates
• Increased gallbladder size and distention with bile
• Darkened and dehydrated muscles, especially the pecs which lose their fleshy appearance

The body temperature of our birds depends entirely on how we handle them for the first days. As the birds are out of their comfort zone 39.5–40.5 ºC at cloaca level (103-105 ° F) they will make metabolic adjustments that generate energy expenditure.

The energy expenditure associated with different metabolic adjustments will be reflected in low weight gain, poor dietary conversion and unevenness in uniformity. If the heat stress situation is strong and prolonged, the birds will stop drinking and eating to a point that death will occur.