I have read somewhere that when they start getting their feathers. I am almost done with the tractor and am trying to figure out when. The weather outside here is 40 at night and 60 to 75 during the day. Any help is greatly appreciated.
Actually you'll want to wait until they are fully feathered especially considering the chilly night time temps. I'd say from 6-8 weeks would be good. :
We have similar temps here in Okla. I started "hardening them off" at around 3 weeks until they no longer used the heat lamp and around 4 weeks. Meantime, I let them have "free range" time in their grow out cage in the chicken coop starting with a couple of hours until they tolerated all day.( 70's-80's) and moved them to the brooder without the light for about 3-4 nights. Now at 5 1/2 weeks they are outside all day and night. I'm still checking them to make sure they move inside at night. Today has been cool ( 40's) and rainy. I provided dry straw for the run, but they went for the wet straw that I raked up into the corners. They are dry and are learning to "come in out of the rain". So far, everyone is healthy and dry.
Temps are ranging 50-70* these days & nights where I'm at. I keep them in the brooder for 2 weeks then they go to a cage in the growout pen with a light for another week or 2 depending on the weather and how fast they are feathering out. I put a piece of cardboard on the cage floor under the light to protect them from drafts from underneath. At 3-4 weeks old I turn them loose inside the growout pen.