If she's gone broody, you'll see the occasional randomly placed BIG poop, they save it up while on the nest then make a BIG deposit
yeah we talk about poop a lot here but it's a handy thing to know. She'll show up again with a bunch of babies and it will be the cutest thing in the world. If you think this is the case, leave some food out for her so she can scarf up something on her breaks from sitting, if you feel the other animals won't just eat it up.
Otherwise, if she's hiding like that, it's because she's wounded.
Generally one that gets loose will come right back and hang around the coop with her pals.
I've caught most of our basically feral chickens with a Hav-A-Hart with scratch or cat food as a bait.
the last, "holdout" hen, was caught be leaving scratch in a cage with the door open for a bit, then one day she was in there and the land owner came up and closed the door and put her in the coop with the others.