How's he doing? This is exactly why I check on little ones before I go to bed. If he's barely moving it would've been best to bring him inside and warm him up in a warm towel. Once he's moving around you can put him with siblings.
That's exactly what i did. Found him at bed time... notice my very adult life pajama pants. Lol
I brought him in, and kept him wrapped in that rag for about half an hour. He started moving around a bit more and feeling a lot warmer to the touch. So i snuggled him up in the middle of his siblings. All of them are good this morning.
Thanks for the suggestion! I read a bit about heating pads you warm them, the while idea seemed q little risky to me at the time though. Maybe When I'm a bit more adept and confident with my handling of kits. Lol