Swollen legs on Campine

[Appy45]

Any info would be appreciated- my 8 wk old pullet Golden Campine is half the size she should be and two weeks ago her legs swelled up and there is heat in them. She eats great and drinks and can walk around but they look painful. Couldn't find help so I started her on antibiotics. Help!

 

[Miss Lydia]

there is something called failure to thrive, which sounds like what you may be seeing in your chick, but the swollen legs I don't know about but I did find this.
https://www.backyardchickens.com/forum/viewtopic.php?pid=4760642