Button quail chicks

[isegal]

Hello, I have 5 12 day old button quail chicks... I've been keeping them in a big plastic enclosure with a roof and a heat lamp. For the past 2 days, I've seen some of them start flying upwards and hitting their heads onto the top, even if not startled, and pecking on the cages walls. I ordered a big outdoor coop for them, but it's not arriving for another week, and I feel like the cage won't hold them for another week. What should I do?