We used similar when we had 2 chicks on accident (broody hen). The other box we use had other size babies in it. I didn't trust them together with 2 being so young.
You'll want a lid of either some chicken wire or hard wear cloth. It didnt take very long before the babies in a box were flying...
My frizzle rooster is down, He normally has a very red comb, about 5 months old. I am very new to owning chickens. Last night it got very cold, but they were all in the coop (same chickens since we got them in Sept, except this Roo as a baby chick from neighbors flock). All of them were totally...