It can never hurt to be cautious of other birds hanging out with your flock. If your flock gets a fatal disease, chances are it came from other birds.
Where are the wild chickens? I have heard there a few places around Phoenix and Gilbert that have chickens running around at large. We are in...
Gently touch the pad under her foot. Compare the bad foot with the good foot. If the bad foot feels harder or if you feel a lump, she could have bumblefoot. Bumblefoot is common and treated with antibiotics.
One of my hens had this last year. We gave her antibiotics and she was quarantined so...