Donuel:

Why is that?, our border collie eats poo too...

My sister had a friend who kept wondering why she kept seeing cat litter in the bottom of the toilet bowl. She finally figured it out; dogs are coprophagic (perhaps an adaptation from the wild for vitamin supplementation), and the dog was taking midnight snacks from the 'buffet' and washing it down with a cool drink from the 'fountain'....

Cheers,