I'm getting some eggs in the nestboxes that I'm not sure who they're from. I was wondering if there was any easy, fool proof way of telling who laid them. I'm not home when they lay so I can't see who the culprits are. I heard putting food coloring on their vent colors the egg as it comes out, but I'm not sure if that's safe...I don't have a way to use the trap nest box method either...I'm completely stuck.