i take my jacks with me everywhere, generally only one at a time if i'm camping though.....my hammock won't sleep all 3 plus me.....or rather my sleeping bag won't sleep all 3 plus me. I've got one that's so docile he'll happily strut along and not go more than 20 feet from me, the other 2 however are very hunt driven and will try and disappear down the nearest rabbit hole and fetch dinner.
Depending on how long you are out, you may want to invest in a jacket for the dog, or at the very least a hi-vis jacket depending on what your dog is like for "going to ground", nothing worse than seeing the sog one minute and losing it the next and spending a while looking for it...only to find it back at basecamp in your hammock but that's a story for another time....