The relationship of chickens to bugs is two-sided.
During daylight hours hens love to dine on tasty protein-rich insects. Grasshoppers, crickets, flies, spiders, ticks, and just about any other six- or eight-legged creature they catch becomes lunch. They even snatch flies out of the air and consider them tasty snacks.
But, come evening, the relationship between insects and chickens switches. When chickens hop up on their roost and settle in for the night they are vulnerable to pesky mosquitoes, black-flies, and various species of gnats. There are even reports of birds being killed by enormous swarms of black-flies, although mostly night insects are just bothersome.
Fortunately it’s relatively easy to protect chickens from these night flying pests. The secret is simple – screens on coop windows. Because some gnats are tiny, a fine mesh is best. The same type of screens that keep insects out of houses works just as well on a coop, but often humans fail to install them. If you put screens on all coop’s windows and close exterior doors when the birds go to roost, few insects can enter to pester the birds.
During hot weather chickens appreciate a fresh evening breeze, and sometimes the dust they create clogs screens. It’s a good idea to hose or brush off the dust when it builds up.
Mosquito netting will not keep raccoons, opossums, or other strong predators from entering. They’ll simply rip through it and enter to snatch a hen from the roost. So, coop windows should have two screens fitted snugly and securely over them. One is an insect screen, best fitted on the inside of the window. A husky barrier of strong wire mesh, like hardware cloth or 1 x 1 or 1 x 2 inch wire fitted and secured on the exterior side of the mosquito mesh will keep out furry predators and protect the mosquito screen from their claws.
It is also worth noting that during brief times when biting insects are abundant during daylight hours, it may be prudent to keep the hens indoors.