Bindi, my 3 year old(well, almost) GSD will run around in the snow like a wild girl usually. But today she was just sniffing the ground(rabbits) and just all of the sudden pulled her left hind leg up and wouldn't walk on it. The she tried to sit and her left hind end just kinda collapsed underneath her. So I got her inside and felt around a little but nothing seemed to hurt. Then she got up and started tearing around inside as if nothing had happened. Then I let her out again and within a few minutes it happened again. Same leg, same thing only she would walk on it but with a limp. Then she sat in front of me but had her left front paw off of the ground. My first thought was oh no, she's getting hip displaysia. But then when she did the front paw thing I thought that maybe the cold snow was just bothering her paws. Both times she was out for less than 10 minutes. The last couple of years it hasn't been a problem being out in the snow. In fact, there were times when we just left her out there because she didn't want to come in.