We recently added some new ducks to our flock. They share the coop with the chickens at night (although the chickens stay up on the roosting areas and the ducks stay down below). I have noticed that some of the chickens are starting to lose feathers on their backs and have some bare patches of skin (see attached photos). I am worried about them being infested with lice or mites and wondered if there is an easy way to tell. I noticed one of the birds "cleaning" herself where the bare spot it. About 6 of our 30 chickens have this is various stages. Any suggestions on identification and remediation would be helpful. Thanks!