My husband has created the ft Knox of chicken coops, nothing is getting in there and I'm adding a baby monitor so I can hear in the coop all the time. I was hoping they could they are getting crowded in the brooder and want out. I will post photos today when they go in.
With the lamp? Whenever you want/feel comfortable/can't escape from your set up. I advise keeping chicks in the brooder until 6 weeks of age, when they go outside without heat (usually at about 4 weeks I'll start only turning lights on at night this time of year)