I would re think putting the foam board on top of the screen, it will actually absorb more humidity from the air.

You are more likely to get bit when feeding in a separate enclosure. I don't know what kind of breeder would feed in a separate enclosure. If you are breeding snakes that is a lot of mouths to feed. Taking them all out of their tubs, moving them to a different tub, feeding them, and then waiting 30 minutes would make feeding take HOURS.