Also if i'm fishing 29* steps away from where the dogs are tied, they don't eat until I get back near them, but they do starve. Once I'm near them, they'll eat the food that's on the ground.
So if you go far enough away, they neither starve nor eat, if you go a short distance away, they starve and don't eat, if you are nearby, they eat when they get hungry.
*I haven't tested different numbers of steps yet. 29 is where the water is deep and that's how far away from the tree they're tied is.