Missing feathers

[vaiaata]

Hello,
Two of our eight hens seem to have lost almost all the feathers on their backs. I first thought at first that the others might be picking on them but I have never seen any aggressive behaviour - they all seem to get on just fine. The rooster mounting them usually causes a few crooked feathers, but not this sort of unsightly damage. Apart from this all the hens, including these two - are very healthy and apparently completely unstressed. For most of the day they have the whole garden to forage in and the fenced-in run is big and kept clean. Any suggestions of what can be causing this and what the solution might be?
Thanks,
Chris in Orlando FL

 

[GoldenSparrow]

Can you post a picture?

 

[chickenbaguette]

Feather picking usually happens around the wing area not the back, anyway.
It's probably some kind of mite or lice, possibly depluming mites. I would isolate them from the other six birds straight away while you find out what they've got, as mites and lice can easily affect a whole flock in a few days. How long have your two hens had this?

You should check them for eggs on the feather shafts and in the actual feather, and does their skin seem normal or has it gone scaly or flaky? Is there any redness around where the feathers were before?

Do their other feathers seem normal, or unusually dry and dull?

 

[vaiaata]

Hi - no it's definitely on the back only. And everything looks pink and healthy. Both hens have had this for a couple of months now. It happened quite quickly and doesn't seem to have spread to other parts of their bodies, and there is no sign on the other hens or on the rooster. I'm trying to work out how to attach a photo. Whitey was being unusually shy and trying to position herself behind things that would hide her back. But eventually I got a reasonable shot. Thanks, Chris