About 12 out of 22 hens have bare spots above tails

[8xnoy]

We have 22 hens and 2 roosters. About half the hens have significant bare spots above their tails. A few have them underneath on their bellies as well. This has been going on a for several months now, with the numbers of affected hens growing gradually. I have been reading and worrying about mites/lice, but had originally assumed it was the roosters trying to mate. Any ideas? If it is mites, would it not affect the entire flock after several months? Egg laying is good, though the numbers are down from early fall. We were getting more than 20 each day and are now down to about 15-18 a day. Any ideas would be really welcome -- I hate the thought of using chemicals!!

 

[sonew123]

moulting? MIne take a good month or two to go through it-

 

[chookchick]

Probably the roosters. The ones that have the problem are their "favorites". You can buy or make saddles to protect their backs, I'll see if I can find the info for that. If you have looked them over very carefully, checked the nestbox and the roost at night, you should have seen if there were any mites or lice. The missing feathers underneath sounds like broody behavior--have any of them gone broody in the last few months? Are these young hens and roosters? You might want to give the hens a break from one or both roosters if they get bad.

Here's a pattern:
https://www.backyardchickens.com/web/viewblog.php?id=4031-Patterns