Do I have a picker or more bugs?!

[SJsChickies]

I have something going on that’s puzzling me. I have 10 chickens. 4 that are April/May hatch date and have been laying. In the summer they had lice or mites and I treated them with permethrin and cleaned the coup really well and they seemed to be better. About a month later, the 4 layers continued to pick at their back, at the base of their tails (the other 6 had ZERO signs of picking) so I did an elector PSP treatment on everyone and cleaned out the coup again even though I didn’t see bugs. Fast forward to about a month ago, another of my girls started laying and 1-2 weeks later showed signs of picking in the SAME spot as the other 4! So a week ago I treated everyone AGAIN as well as the coup. But the 5 that aren’t laying yet still have ZERO signs of picking. Could one of the layers be picking on the others while they’re in the laying box!? Why are JUST the layers picking? They are all on Kalmbach 20% protein feed and get BSFL for treats so I feel like they are getting enough protein. At this point my husband doesn’t think it’s bugs anymore cause how many times since the summer I’ve treated them. Any thoughts?

Oh also, one of the treatments was a pour on ivermectin just in case it was burrowing mites.

 

[FrostRanger]

Pictures?

 

[SJsChickies]

Pictures?

They all look like the first pic. The second pic you can see the striped one too. The two dust bathing look just like these two. You can see my black star in the back of the second pic looks perfect. The other 4 non layers look like her. The newest layer doesn’t look as bad as the 4 older layers but she has broken feathers at the base of her tail and you can see some of the fluffy white feathers poking through.
ETA: no roosters.

 

[FrostRanger]

Looks like feather picking to me. What's their diet like and how big are their coop and run?

 

[SJsChickies]

Looks like feather picking to me. What's their diet like and how big are their coop and run?

They are on Kalmbach 20% protein pellets. The treats they get sometimes are just black soldier fly larvae. Run is about 125sqft and the coup I’d have to measure to get the exact size. They only go in the coup to sleep or get the the laying boxes though and they have 4 different 2x4 perches that are about 4ft long each so they aren’t on top of each other (unless by choice which does happen lol) when they sleep.

 

[FrostRanger]

They are on Kalmbach 20% protein pellets. The treats they get sometimes are just black soldier fly larvae. Run is about 125sqft and the coup I’d have to measure to get the exact size. They only go in the coup to sleep or get the the laying boxes though and they have 4 different 2x4 perches that are about 4ft long each so they aren’t on top of each other (unless by choice which does happen lol) when they sleep.

I see, diet and space look good, in that case I would put pinless peepers on the offenders (which are usually the ones with perfect feathers) for a bit to see if that helps

 

[SJsChickies]

I see, diet and space look good, in that case I would put pinless peepers on the offenders (which are usually the ones with perfect feathers) for a bit to see if that helps

I didn’t even think of those! Thank you! I’ll get some and hopefully it helps!