We've had chickens for 4 years. In the last 2 weeks, we've had a hen (1.5 yrs old) start to lose LOTS of feathers. They're from all over her body. She's interacting fine with the other hens. She's roosting during the day some and sleeping in the nest box. I don't think she's been laying for 2 weeks. Is this normal molting? Should I be doing something about this situation? She doesn't seem to have obvious symptoms on her head.