That sounds like a good plan. As you said, you can see how it goes and if it doesn't work out, you can put them back in the brooder again. My seven that are in the brooder now had to be moved to a bigger box because the new coop for the older hens won't be finished for a few more weeks. They are really old enough to move outside, but I don't have a place to put them just yet. They love the new box! It's big enough for them to fly around in and they are doing that quite a bit. Keep us posted on your chicks and let us know how it's going!