I guess all of the information I've been given thus far re: space requirements has been wrong...back to the drawing board!
If you have a peaceful flock in a cage that size, you might keep doing what you've been doing but file the birds nails to a reasonable length and make sure they have plenty of enrichment/things to do.
The "1 square foot per bird" bit you've probably heard best applies to battery cages—it's a space ratio at which the birds won't constantly fight, but they won't have enough room to exercise or get out of each others' way.