It's best to keep a broody separate, because otherwise she may abandon her hatching eggs and sit on the ones the others are laying in the nest box. She doesn't actually need any 'off the nest' space most of the time, just shift her off for a few mins a day (and feed her when she is off) and if she is reliably broody, she will go back as soon as you let her. I used to use an old tea-chest for a broodybox, with detachable wire mesh across the front. Once you have a chick or so hatched, you still need to keep her away from the other adults for a few days, to protect the babies. She will still be looking after her babies for 3-4 weeks (possibly more, depends on the weather and her temperament)....

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