Depends on the weather, and what pen is free for them to go out in. I only put them out in "good" weather until they are older and I always run an extension cord outside to run their warmer for them if they are still on heat. And unless I can be right there with them, smallest babies don't go outside unless I have a secure pen free for them to use. But in the right circumstance, I let newly hatched chicks go outside.
Today is very windy, so only the 3 week olds are outside and I set up wind breaks for them in the pen. They've been off heat for more than a week, so I did not take a warmer out for them since it is sunny enough for them to keep warm.
Momma hens take chicks out soon after hatching, so as long as you have a heat source, wind protection, predator protection, you can take them out when you feel comfortable doing it. No set age requirement for the chicks, just depends on your level of comfort.
Thank you so much! That was EXACTLY what I was needing! I didnt think a mama hen would not let her chicks out regardless of age so I figured they had to be hardy enough to go outside pretty soon. Although, we lost one today and im baffled. They did get the paper towel pulled up in one corner and got to the pine shavings and that one was getting pretty excited over the shavings so im thinkin it might have gotten a belly full. ...idk but we buried it and said our goodbyes and scratched our heads as to what mightve happened.