One of our New Hampshire Reds started limping a couple weeks ago and we figured it was a leg injury. It started seeming better, but now she seems to be having a lot of trouble staying up on her feet and plops down on her bottom. I did notice one picking at her tail feathers yesterday so we put her in a cage on the porch with food and water and hay. She doesn't have any visible injuries, but her whole back end seems somehow undeveloped or shortened. On her own, she started going in the coop at night with the 3 oldest chickens that we got last year instead of the other 4 month olds. They also seem to be the only ones sneaking onto the back porch to check her out. I don't know if that info matters, but maybe it is somehow significant. Any help would be appreciated!