Hello, I live in Michigan and it has gotten pretty cold here the past two weeks. I have two radiant heaters in their coop. I let them out in a covered run that has plastic up to block the wind. I noticed today of of my Silver Laced Wyandotte chicken that her feet look grayish. Is this frostbite? I never noticed it before. If so, what should I do? She will not go into the coop is walking fine but does pull her feet up like she is cold.