I know why dogs can't eat chocolate. It's something in the chocolate called "theobromin" (I am not sure if it is that on English) but even a little amount can 'cause them big trouble. Dogs that have a sensitive belly can die of a small amount of theombromin, but dogs that can eat anything finely without vomiting, can tolerate more.
Very nice composition! The Rottweiler reminds me of my housemates dog. He wolfs down ice cream while my aunts dog just slowly licks it up. It was pretty funny to watch them.
Again, very nice composition!