After much debate, and the fact that temps are heading into the 20's tonight, I brought Iris and the eggs inside.
She is now in a large cat/medium dog crate with a brand new cat litter pan as a nest, and a dark towel draped over the crate.
She can stand up with room to spare in the crate, the litter pan keeps everything in place in the nest and there is space in front of it for food & water bowls and a poop area.
She has dropped some weight and by keeping her inside I can make sure she's eating enough.
The plan is to take her out to the run for 10 minutes a few times a day to let her stretch.
Hope I'm doing the right thing.