Why Is My Dog Having Diarrhea All The Time But Still Acts Fine And Wants To Eat And Play?

I had a 2 year old Bassett Hound that started having severe diarrhea. He had all of his vaccinations, and I had him wormed and checked for all parasites that could cause this. I gave him a bland diet and made sure his water dish was very clean. He had an odd smell (like sour apple juice) and began licking his rear so that he was actually eating his own waste as it came out. The weather was getting colder and i asked the vet if he could check him into the clinic for testing. He told me that i would have to give him $1000.00 to start any testing or treatment on a dog with chronic diarrhea. He wouldn't take payments and i didn't have that much money, so i lost my dog. He was put to sleep, and i was heartbroken. I never even found out what was wrong with him. I think that vet insurance may be a good idea for people who can't come up with emergency vet fees. This year i also looked up chronic diarrhea on vetinfo.com in the Encyclopedia of Canine Veterinary Medicine, and it said that there can be many reasons why this happens. I feed the 2 dogs i have now a quality dog food that is mostly chicken and rice, and i add cooked plain chicken to this at times. The only other treats they get are cooked peas and carrots and dog biscuits. When one new puppy (a 5 lb Dachshund) had been vet checked and still had diarrhea i gave him some plain yogurt and it cleared up right away . Thank-you to the people who gave out this information.