I have sperated, brought indoors, and have been doing physical therapy with this chicken since it was injured. My puppy got ahold of it. When i got it it could get off of its side and was being stepoed on by others. Now it looses balance on occassion, but can walk and even run. Therefore, i dont think development is going to ve terribly destroyed. It has come a long way.
Leghorns are very early maturing and even hens have massive combs and wattles. I'd expect a cockerel to have an obvious, fully developed comb and wattles by now. That said, Gray Farms is right - the birds growth could easily have been impeded by the injury.