What are the signs of heat stress in broiler chickens and what should I do?
worked example · Caribbean · Open curtain · Ross 308 · 1,500 birds
Signs of heat stress in broilers include persistent open-mouth panting, wings held away from the body, reduced feeding, increased drinking and birds spreading toward cooler areas. Severe cases may become weak, collapse or die. FAO and breed-guide heat stress guidance warns that intake and growth often decline above roughly 30C, and earlier in high humidity; heavy birds near market age are especially vulnerable.
Act promptly: open and manage curtains for cross-flow, use circulation fans to move air at bird level, and make sure all birds can reach plentiful, clean water. Shade water tanks and lines where possible, flush hot water from drinker lines and check drinker flow. Stop catching, weighing or transporting birds during the hottest hours. Collapsed birds, severe distress or rising deaths require urgent veterinary help while cooling measures continue.
FAO tropical poultry guidance prioritizes shade, air movement and water in open-sided houses. Reduce roof heat with insulation or suitable whitewashing; roof wetting can also help where practical without soaking litter. Shift the main feeding to early morning and late evening, and plan lower stocking in hot seasons rather than accepting extra deaths. Avoid adding indoor moisture when humidity is already high.
In a naturally ventilated Caribbean house at 31C, for instance, the example flock of 1500 Ross 308 broilers at 12 birds/m2 needs close observation, especially as birds approach the target 2.8kg at 42 days. Check conditions where the birds stand, not just outside the house. The example's realistic FCR is 1.68 versus the standard 1.55, illustrating why planning should reflect actual house conditions rather than ideal breed performance.
Record daily water use, feed intake and deaths alongside temperature and humidity. FAO poultry development guidance and breed management guides put normal water intake at roughly 1.6 to 2.0 times feed intake by weight under thermoneutral conditions, with a higher ratio expected in heat. A sudden fall in drinking is a warning to check supply immediately; persistent distress or deaths should not automatically be attributed to heat, because disease and other problems can look similar.
This is field guidance, not a veterinary diagnosis; seek urgent local veterinary advice for collapse, severe breathing distress, rising deaths or signs that persist after cooling.