I love in northern California we just started getting 100 degree weather for the first time this year. I've just notice 1 of my. Chickens have feathers missing & red skin on her behind. What kind of pest is this. I let my chickens out to free range for all day then I close them in at night. Does them being out make them be more prone to pest. Is there a permanent treatment to this? I want to treat it before it gets worse. What do I need to do?