Do you know how he got outside? How cold does it get where you live? My yearling lesser was gone for about two weeks in October of last year and I found him by the entryway between my kitchen and garage. I let him settle in for a couple of days and monitored his behavior. When I started to thaw out some rats for my other bpz, I noticed he was sniffing around his rack and he pounded 2 rat pups asap. Keep us posted on his condition. BTW, I live in southern Cali so our winters are pretty mild.