Our Buff Orpington hen, age unknown (maybe 3 years old?) is not moving around real well. She cannot seem to hold her body up, legs seems to curl under the weight of her body. This has been going on for about 24 hours. 3 days ago, she spent the night outside, in the protected space below our coop while it was -7 outside and snowing! Showing slight signs of frostbite comb, and has a history of being a real tough bird - survived dog and raccon attacks with previous owners. Found her in coop last night wedged between nesting boxes and short roosting pole. Removed her and have brought her into house - eating food well, not drinking much water, poo a little runny, eyes look alert. Just doesn't seem to move well, leaning against things. Have checked her legs and am not seeing signs of trama, blood, abrasons, etc. Is this related to the cold night outside, shock or something else? Thank you, in advance, for any advice.