For the most part having three isn't much different from having two. Cassius is senior citizen with thyroid and cushings issues so his activity level is very low, but he does rumble with the younger boys a little here and there.
Feeding time is always interesting. Cassius and Bo are pigs and Max will almost always leave a meal for hours before eating it. We've been working on that since he was about 6 months old. A little chicken broth usually helps coax him to eat, but he still takes his time to savor the meal (aka get distracted by every sound before returning for another nibble). the other two circle like vultures hoping he'll drop some.
The three all sleep in the bedroom on blankets by the side of the bed. Bo thinks he should sleep with us, but he's learning that once both of us are in bed, all dogs sleep on the blankets on the floor.
We have it real easy here for walks and woods time. We live on a very quiet, circle drive in the 'burbs, and we have the creek and woods right outside our back door. No neighbors behind us til you cross the creek and head up 200 yards of thick wooded hill. All this makes it ideal to let the boys romp.
We also have a fenced in section of our yard for whenever the boys want to go out. the laundry room has an outside door with a dog door that leads right to their run and this is available all day and night until its freezing out. If they want to be inside they have the run of the living room, den and kitchen. All bedrooms are closed, otherwise we find our laundry and other items dragged downstairs and outside.
Without some of that convenience I'm sure we would have much more work on our hands.