Why would a dog have leaking mushy stools throughout the day? For 8 years?

This poor dog has leaking stools every single day. It has gone on since it was a puppy. It's been to several different vets and been on many types of dog foods.So far, nothing has worked. Do you have any suggestions?The dog is a little overweight at the moment... and not dehydrated.

A food allergy or irritable bowel syndrome are the most likely causes. There could also be some abnormality in the GI tract itself, but without a visual inspection of the whole GI tract you aren't going to know that.Just having tried different foods doesn't rule out a food allergy because it could be to something other than the main ingredient in the foods. As this has been a chronic issue, you may want to consider actual allergy testing to determine if there are foods that are causing the issue. You may also want to discuss the possibility of an irritable bowel issue with your vet and see what options you have as far as foods or medications to decrease GI irritation.