Chickens are highly sensitive to temperature and light, so changing these factors can help or hurt a flock’s well-being.
Gregory Archer, a Texas A&M poultry science professor, discussed ways to reduce bird stress Wednesday during a Penn State webinar.
While some stress is good for the body, too much can decrease productivity and immune function while increasing health challenges and aggression.
Almost anything in a chicken’s environment can be a stressor, including diseases, poor ventilation and changed routines.
Farms may unintentionally create crowding stress by stocking a large flock, then having greater survival than they anticipated, Archer said.
Temperature is one of the most common and obvious sources of stress.
In Texas and other Southern broiler states, getting too hot is the main issue, but in northern climates like Pennsylvania’s, cold stress can also appear.
Chickens generally prefer temperatures of 64 to 77 degrees.
“That’s relatively cool,” Archer said.
If they’re too hot, birds will start breathing out of their mouths, stop eating, increase their drinking, and lift their wings to get air under them.
These symptoms tend to show up after the birds have already been heat-stressed for a bit, since prey species like chickens don’t like to seem vulnerable.
“If they’re showing those behaviors, that means a predator can be like, ‘Oh, something’s wrong with that one. He’s going to be an easier one to get,’” Archer said.
Some proposals to manage poultry heat stress, such as restricting protein in the feed, have shown little effect or create unintended consequences like reduced productivity, Archer said.
Drinking cool water is a solid way for birds to cool off, but that’s not easy in poultry houses with their long water lines. The water birds get is often warm, sometimes even hot, Archer said.
That means ventilation is key to cooling off commercial birds.
Some research shows sprinklers may increase the cooling value of fans.
In cattle barns, sprinklers provide cooling through the evaporation of the water off the animals’ bodies.
In a poultry house, the light drops of water are intended to mimic rain and prompt the birds to stand up. That gets them off the litter, which is warm from microbial activity and the sitting birds’ trapped body heat.
“If you can get the chicken to get up and then the wind’s blowing in there, you can actually cool their bodies off,” Archer said.
Archer is researching whether pulses of light could provide a similar impetus to move around without introducing extra moisture into the house.
Getting the birds up and spread out for 10 minutes per hour might be enough to cut heat stress, and lighting changes are easy to program in most poultry barns, he said.
While light may help with heat stress, light sources can be their own cause of stress to poultry.
Birds can see a wider range of colors than humans, especially in the red, blue and ultraviolet spectrums.
One layer farm Archer visited saw its productivity drop 20% after putting in a bunch of cheap lights. His spectrometer showed the bulbs put off lots of green light, which is believed to either stress layers out or tell them to shut down reproduction.
Once the farm replaced the bulbs, production returned to normal, Archer said.
Little research has been done on lighting for turkeys, but broilers do best under blue and green light. Layers and ducks perform well under red light, he said.
Source:Lancaster Farming
