Chicken not gaining weight

[chickypic]

Looking for an answer to why my chicken isn't gaining weight, after moulting. Breast is bony.
Eating and drinking

 

[Sjisty]

Did you check for mites? I have a hen in a similar situation - very thin. Yesterday morning I had her in my lap trying to see if there was anything wrong. I found tiny red bugs/mites running down her feather shafts. Needless to say, I spent the rest of the day treating everybody else and the coops.