Can you provide a picture of your existing coop/run? It might help us come up with suggestions on how you can temporarily modify it while the new chicks meet Ivy.
That is not entirely accurate. We would need to see the setup. Perhaps the brooder is a large dog crate that wouldn't fit through the cleaning hatch on a smaller raised coop or wouldn't fit without removing nest boxes/perches/etc. because the height of the brooder and ceiling height in the...