I discovered a big patch of missing feathers on the bottom half of my pullet's back this evening. The skin isn't torn and there is no swelling or bruising, but a number of feathers around the area have also been damaged, mostly at their tips. Here she is on my lap with her wings spread a little: Mischka is 11 weeks old and otherwise seems perfectly healthy (except she has been treated for mites this week, along with the whole flock and coop and run, as explained below). She has a normal appetite and has been keeping hydrated; the weather has been cooler here this week after a dry, hot spell with smokey conditions last week (we're in Northern California). Mischka wasn't tender when I handled her, or behaving strangely at all, and she didn't seem to even be aware of the problem. In fact, it wasn't noticeable to me until I gave her a full body exam today looking for mites (I only found the them on her face) because her wings cover that part of her when she is meandering around. I'm not sure how long she has had this problem, because I've been busy dealing with the mites the last few days and in a flock of 21 I can't cuddle every chickie every day anyway (okay, that's a lie....I really do try to but they aren't always in the mood being the independent teenagers that most of them are!) She's a sweet and social bird who gets along with everyone in the flock...in fact, my whole flock is very peaceful so I'd be surprised if it was another pullet that did this to her - but the two older girls that are laying already are not afraid to claim their territory over the young girls or the two cockerels! Also, there's a fair bit of hustle at bedtime when all the chickies vie for their favourite spots on the roosts...there's plenty of space for everyone but of course they all love to smoosh in together and one or two of them tumble down every night in the process. It's possible she fell but I can't imagine her hurting herself this badly.... Maybe one of the cockerels was trying to mount her? They're both pretty chill cockerels too - only my 19 week old D'uccle has even tried to mount any pullets and I've never seen him near the younger girls. He's little though, so when he has tried to mount the big girls he's had a hard time grabbing hold. (Poor funny little dude!) The only reason I noticed it was because we had a minor red mite issue so I spent the day giving each chickie a full body exam and picking mites out of the cheeks of all of my fluffiest chickies. I sprayed the coop yesterday with Permethrin 10 and misted the flock on their roosts last night. I don't see (and haven't seen) any mites around the coop at all or on any of the chickies without beards or muffs, so I'm hoping we're through the worst. Each chicken with muffs or beards or crests or other poofy bits had a few mites around their eyes and one or two had them under their beak at the edge of their beards. There were no mites elsewhere on any of their bodies. Is it possible she had some on her back and picked at her own feathers? None of the chickies have been seen to be scratching themselves at all but who knows what they do when I'm not around! Or, do you think the spray could have somehow damaged her feathers?? I feel like I could write a novel here so I'll leave it at that and just answer questions as they come up. This is my first major issue with my chickies so hopefully it's something basic like she's moulting her teen feathers, haha.