How soon after toy gave them their box did they start to exhibit breeding behavior?
I'm thinking that the best way yo ensure they get the break they need before starting another family is to remove the box for a few mo the.
The break should (I was told) be about six months from after they stop feeding their last clutch. That would mean giving the box back in September or October, giving them a month or so to investigate the box, mate again, and start laying again. I know that sounds so far away, and I LOVE baby birds so much, but its healthier for the parents to have this break. You don't want to lose your hen from breeding too frequently.