Feeding it chicken starter and after we saw this with her leg we went and got her some poultry vitamin supplement because I did a little reading and found that could be the issue
(1) Are you new to chickens / when did you first get chickens? I am not new to chickens my parents have been raising chickens since I was around d 6
(2) How many chickens do you have right now?
Around 15
(3) What breeds do you have?
All kinds of chickens including Easter Eggers, Silkies...