I remember reading somewhere that was the biggest threat to their temp - moisture - amd I thought specifically feet.
My oldest hen is 5, the buff, and at her old age she won't step on ice or snow, unless she absolutely has to, lol.
My biggest concern this time of year is Hawks. The ermine I had slinking around their run a month or so back has moved on. Had it's fill of meadow voles, couldn't get into their run, and thankfully took off.