At 4 weeks old they should be down to 70 degrees,
right?
I have a large dog crate in the pen/run with a heat lamp
inside and covered on top and 3 sides with a thin
blanket.
I leave the lamp on during the morning and then again
when it starts to cool off so they can go in and get
warmed up if needed.
Mine are 4 weeks old also but are feathered pretty
well.
They are having a blast outside!
They never want to come in.
I may leave them out at night with the same setup.
(Closed inside the crate, that is)
As long as you can keep the temp at 70, they'll be fine.
It's good for them to get exercise and fresh air.
I think it makes them healthier.
*End of my book*!