hello everyone I have 15.6 week old black australorp pullet and she has a whitish-circular bump on her upper leg. She arrived a week ago from cackle hatchery and I kept her in a 4 foot by 4 foot wide wooden hutch in my coop to introduce her with my flock. Since she arrived she has been sitting frequently and hasn't walked much, but she still ate, drank, pooped regularly and did walk a bit. Last night I took her out of the holding hutch so she can roost with my other hens and I saw her leg has a white wart on the top of her leg. That is the only abnormalities about her, here are some photos below. What could this be?? Thank you for any help.