She still eats and seems healthy and energic. The only thing is that she seems to have stopped growing. What can cause this? Another thing I noticed at her is that she lost some feathers, leaving a few areas a bit exposed. I checked under her wings and there were big bald spots on both sides. I'm worried that it has something to do with her not growing. I read that they change their feathers yearly, but it's kinda cold now, she's the only one with this going on and it seems kinda strange to me that she would do this in october. For comparison, this is her (the orange one) next to another chicken, exactly the same age. You can also see around the tail these gray spots, which are the fur or fizz or whatever it's called from the base of the exposed feathers. In between the visible feathers there are tons of new ones growing. Also, forgot to mention that I started deworming today so I'm looking for other possible causes.