Personally Steven, I think it is the small flies that inhabit some lofts and they get into the pigeon feathers, bite the pigeons, stressing them during the night, lay their eggs and rapidly multiply. They are not much larger than midgies. I have heard them referred to as pigeon mosquitoes when fanciers were talking about that subject some time back. Not so much the lice and mite, however, they also bite the pigeons, so who knows how the infection enters the pigeons' system. I use Ardap spray. i don't know what Kevin uses.