Why is my hen losing her feathers?

[ChickensLover16929283]

So recently I noticed my hen having missing feathers under her. I don’t what is causing this does anybody know?

 

[Eggcessive]

Is she acting broody, or spending time in the nest box sitting on eggs? How old is she?

 

[ChickensLover16929283]

Is she acting broody, or spending time in the nest box sitting on eggs? How old is she?

I think she is around 1 or 2 years old but no she isn’t broody. I just don’t know why she is missing a big chuck of feathers under her. She is perfectly healthy as well