Separate or together?

[Tinman0ut]

Is it best to wait till my 1 week old chicks are mostly/partially/fully feathered to put my 3 week old chicks out? Or is it “acceptable” to put the older chicks out first? I have 2 brood lamps so can keep the coop and brooder warm (overnight lows are in the mid 50s) will honestly probably be waiting till the older chicks are feathered more (they still have chick fuzz on their heads and bellies but shoulders and saddles are coming in nicely) before I take any action though.

 

[DobieLover]

I would move them all to the coop if you don't already have adult birds there. Those are really warm temperatures.
You could use a heat pad without an auto-off switch inside a huddle box for the little ones. Make a cave out of the heating pad using a piece of metal fencing so they can get under it. This is how momma heat pads are constructed.
Just make sure you are fully predator proof and no drafts will blow on them inside their coop.

 

[rosemarythyme]

I would move them all at the same time if possible, since they're already familiar with each other, so no need to have to reintegrate the younger birds with the older.