What causes a chicken to develop a crooked toe?

[dlcoops]

I hatched some locally purchased eggs just before Christmas. They're now 9 weeks old, I was looking them over last night and noticed a couple have toes that are slightly crooked to one side or the other. When they hatched I had looked them all over good and none had a crooked toe. What would cause them to develop it now? Twice I have given them Durvet's vitamin and electrolytes with their water. I feed 18% protein chick starter/grower from the local coop. Any help is greatly appreciated.

 

[LoveThemBirds]

Sometimes with animals,their born that way.Deformed toes are common,the chicks toe could just now be developing crooked.