I keep mine in 2x4x4 foot boxes. Mine are by themself until they are coming to me freely for their bottles. Usually within a few days. I then let them out as a group to feed on their bottles and introduce them to fresh greens and pellets and such, and for exercise. I do however seperate them into their seperate pens when I put them back to prevent some of the fawns from licking pee from the less dominate ones. Too much stimulation can cause the fawns to get swollen and possible medical problems and if you happen to be bottle feeding a buck fawn the problem could get worse. Also with their rumens not quite totally functional I'm not totally sure that too much urine would be healthy for the recipient. You may also create a problem of eating pellets from one another which is a bad habit as it would readilly spread things like ecoli not to mention parasites. After a while they will start moving away from each other when one tries to lick the other if they haven't been allowed to do it when younger. Rick