Bare bum and chest

[Shaz1522]

Hi everyone
I need some advice.
I have a flock of 8 and 4 have bold bums.
One of that 4 had it all on her chest too.and now above her legs( she's the worse) and thinner than the rest.
They lay every day.no sign of lice or mites.no sign of bulling.they all eat well. They are about 18 month old..

 

[Wyorp Rock]

Do you have photos?

Often bare bums can be due to feather picking. What do you feed including treats and how much space is within the coop/run?

 

[Shaz1522]

I feed layers pellets and bit of veg some afternoons
Free range at bottom of garden.
I thought maybe pecking but nothing around the neck or back?
I did have a feather packer a few months back so rehomed her. But the one has lost more feathers since the feather packer went.?
I'm baffled. I checked for mites and lice.they are on wormer this week.
I'm just at a loss.all seem happy and lay every day

 

[Shaz1522]

I brought the 4 in an hour ago.put baseline on 3 of them and sudacrem on the worse one as hers looked a bit red unlike the other bare bum ones