My 3 month old chihuahua/terrior mix puppy is constipated and I'm wondering is it common in a puppy?what might have caused it.And is there anything I can do to help him out?I hate to see him uncomfortable like this. Anything natural I can try a product I can buy would you reccomend getting something from the vet.I've never had the experience of owning apuppy,I was four when we got our cocker spaniel at 6 mo. of age so even the slightest problem I freak out so....