Broodies and 3 day old chicks - Outside overnight!?!

[BroodyTooty]

Help/Advice needed please!!! First time hatcher!!!
I have three broodies raising four chicks they cooperatively hatched in the last few days. I had a pet gazebo attached to my coop as a mini-brooder/run to transition them into.
Unfortunately, they ran down the ramp today and couldn’t get back up apparently. They nestled under the ramp with one of the broodies. We removed the gazebo in an effort to pick up the chicks and place in the coop. Mommas aren’t having it and I’m afraid they will hurt the babies while attacking me.
They spent the last few hours moving about the big yard schooling the chicks. I’m afraid with temps in the 40’s overnight and some wet weather in the mix this week, it may be much too cold out there.
I put lots of straw in the gazebo and made bucket nest boxes with shavings in them, but what’s to say they will go in there? Right now, they are shielding the chicks under some bushes.
I am seeking advisement on how important it is to get everyone inside the coop or whether mommas should be able to keep them safe overnight with body heat and straw if they use a box.

 

[Yardmom]

The temperature is not a problem. Hens can raise chicks in winter.

 

[rosemarythyme]

I'd worry more about predators than the weather, if that gazebo isn't in a secure location. I raise 2-3 day old chicks outside in similar temperatures, with rain, without benefit of a broody (or in your case, multiple broodies!)