4m x 3m Omlet pen, cube, new auto door still boxed and coop light

[Willow]

One of my chickens has had a featherless chest for some time now . I've sprayed with gentian spray (resprayed today) but it's not helping. I assume the other chickens are pecking her but I haven't seen any bullying when I've been out. They free range most of the day so she can get away if she needs to. She is also skinny but does get access to food and when I've gone out with treats she gathers around with the rest and there's no problem. I've wormed them all recently.I assumed moulting initially but it's gone on too long.

 

Any thoughts ?

[McChook]

Have you tried anti pek spray? Omlet sell this and it tastes horrible to chickens.

 

One of mine has a bald spot underneath where I assume either she's plucking herself or one of the others has been picking on her - since using this the feathers have started to grow back a little. It may help...