I believe that it's okay to let them free range once they are about the size of a regular chicken. By this time, they should be able to fend fort themselves if some animal tries anything funny. I keep my turkey single and she is perfectly fine since she interacts with my chickens (she was raised with them and prefers them even to her own kind), so I am certain a trio would be perfectly fine. I would suggest that you get them all as the same breed, as I feel that turkeys do better with their own breed, especially if you are thinking of getting offspring. Hope this is helpful!
we have a bourbon red. we bought 2 turkeys in april with 9 chicks. one of them didnt make it. our bourbon red is a tom and he and our 3 accidental roosters we threw out of our chicken pen when the roosters started being mean to our girls. now they free range and hang out with our goats and roost on top of our chicken pen at night. our turkey was a little weird when he was younger, he would peck everyone in the eye, our baby goats, the dogs, if he could,so i had to watch him, but he finally grew out of that. he is a pretty boy and talks to us, the roosters dont have as much personality as he does. we are going to build a clubhouse for them to roost in for the winter for some shelter.
what do you plan on doing with your turkey or turkeys? i like the heritage breeds for many reasons. i have heard toms will sometimes fight to the death but our boy doesnt fight with the roosters, they all hang out together and have only had a couple of very quick skirmishes and since they have their order established they are buddies. they say turkeys need a lot of room, so i would free range them when they are big enough to be out. we would like to get another bourbon red , a hen, maybe in the spring.
Turkeys and Chickens shouldn't be kept together bc of black head and u can free range but after they know where they live if u get a heritage breed they can usually fly but a commercial breed will be less adept to flying