We have 2 chickens and they seem to have lost the feathers around their vent, and they are now short shafts. The area is red as well. We have not found lice but we did dust them for lice, and cleaned out and dusted their coop. We have dusted them a further 3 times but they are still red. It does not seem to bother them, they are eating, interacting and running around. We have been getting less eggs of late, but it has also been very hot. As I mentioned we have not seen any lice. Any suggestions?