I thought that once a chicken had fowl pox (dry) they established immunity for the future. Not so for my girls....Each year when mosquito season begins chickens get black sores on their combs. So far they don't seem terribly bothered (I dab antibiotic cream on the scabs) but I hate the idea that they are being bitten every night. The last few nights I've been spraying Yard Guard in their coop an hour or so before they head in to roost, but that is probably not good. Would moth balls be OK to use in the coop? Ventilation is good in the coop. I've thought about regular window screening over the hardware cloth but I think that would cut air flow too much. We have no standing water, but mosquitoes are a problem every summer. Bug zappers attract insects so that seems like it would just pull in more mosquitoes to the area. I spray the coop with permethrin for mites, etc. every couple of months, but any residual effect doesn't seem to deter the mosquitoes. Anyone have suggestions for methods that are effective?