We got our guineas at about 2 weeks of age. Never had a heat lamp on them. Our guineas (we have 4) are housed with our ducks. They were started on gamebird starter also. Now they just eat what the ducks do. We free range them when we are outside. They are easily herded back to coop when time to go inside. They belong to my middle son. The just love him. They don't run from people, and are more intrigued by them then the ducks. Normally guinea lay eggs in places they can hide, but since ours are in the coop, they lay egg there in the same nest that the ducks use. They love to look at themselves. They like to come up on the deck to look in the siding glass doors to see themselves. We have also put a mirror in the coop and they don't come up on the deck as much. We have a lot of wild turkey that come through the yard, and they hide in the coop when they come. They don't like the rain, but don't mind the snow, which I was surprised to find out. Once they are outside in their coop, you should keep them in the coop for at least a week, so they will know where to come home to. If you don't want them to fly over your fence (if you have one) you can clip their wings. We don't do that, but our friends do. Good luck, they are really funny birds. We love ours!