I just picked up 2- two week old bummer lambs. They have been vaccinated, docked, castrated. I have the lamb replacement and started the regime last night. I am feeding 4X/12oz. warmed to 98 degrees. The question I have is that they were living at sea level, with cold temps in the 40's and maybe high 30's. We are at 3100 ft. and it is in the low 30's sometimes high 20's. I have them in the barn- concrete floor covered w/straw, but wonder if they need additional warmth for night temps. It appears they sleep together to stay warm. Thanks for any advise. I want to be a good surrogate mom.