Can you show me your secondary/stage 2 brooders? For chicks 3-6 weeks

Thanks to all of you and plenty of reading, I think the initial brooder I set up is FANTASTIC! Love it--day 2 and all 27 chicks made it through the night just fine. Giant dog crate, both halves connected, x-large puppy pads duct taped over wood shavings. Heat lamp attached securely to a microphone stand (easy to move up and down), two waterers, two feeders... The two halves are working out great because I can herd them into one half to clean the other and then back. Also works well for checking vents and overall health with two sides.

But from reading what all of you have said, 24sf will not be enough space after week 2. We have a ginormous insulated Morton building where they are staying--most likely the place where their secondary brooder will be.

Weeks 3-6, the chicks need 2sf per bird? Ultimately 4sf per bird or more for adults, correct?

What should I do to make a secondary brooder? I was thinking of three watermelon containers with lights at either end, cut out and connected with zip ties and big wide doorways for them to get through.

Any other relatively cheap ideas? I also found a HUGE screen patio system, all linked together that I could probably put in the garage. But what bedding over concrete? This is our garage--not really meant to be a barn.

Could you show me pics and locations of your adolescent brooder?

Or would you move them into the coop with a heat light at 3-4 weeks?

And by week 2, I'll be back to work teaching. If chicks are checked/fed/watered at 7am, will they be ok until 2:30? Or do I need a mid-day chicken-checker?

Sarah