All collies varie in size. Some can weigh up to 110 lbs. But that is for a large bone too! But if your dog is medium. 80- 90- lbs maybe ok if they exercise daily. But if they lay around and build up the weight then that isn't good either. It can put a strain on their heart.
Answered by collies4u - 11/1/2010 4:00:16 PM