Chickens behind

[celestialtom]

This is the best I can get. This chicken behind is red on her back side This the best picture I can get. It is bare on her back side and red

 

[nuthatched]

Have you checked for mites? She could be getting picked. What's their diet? Coop size for how many birds?

 

[celestialtom]

I put DE earth in the coop it is supposed to take care of the mites. I have 4 Road Inland reds, with nesting box the coop itself is 3 by 5

 

[coach723]

So you have confirmed mites? DE isn't going to help and may cause respiratory irritation, both the birds and you. You need to use a permethrin product, there are sprays, concentrates, and poultry powders that contain permethrin, lots of brands, I will picture a couple below. You need to treat the birds and the coop (sprays work best in the coop to get into all the nooks and crannies) at weekly intervals, usually at least three times. The chemicals kill the bugs but not the eggs, they will continue to hatch, so repeat treatments are needed until you get them all. Remove all bedding and nesting material each time, discard or burn it, and replace with fresh. You can also use Elector PSP (spinosad) which is supposed to work with one treatment, but it's much more expensive.