In all honesty, he probably does run miles each day. He gets at least 2 hours of off leash time while we are doing chores, or playing with the kids outside. It isn't uncommon for him to get 5 hours off leash time a few times a week. He spends the entire time chasing whatever unfortunate bird happens to land within a 150 yard radius.
I have noticed the last couple of days he is panting heavily and takes a while to recover after a long hard run. It is also getting warmer, so that might have something to do with it.
Trevor, he is 11 months old now.
Either way, better safe than sorry. I will make a vet visit znc increase his intake. I'll try to fatten him up with some extra treats like the satin balls.
I'll update in a few weeks when I have some time to see any results.