I received 3 new birds last week, and they HAVE BEEN QUARANTINED. When they first arrived, they were dewormed, and I applied Frontline on them for mites/lice (These are show birds, not for eating or laying). I don't find any moving critters on them, but I still see egg sacs on the base of the feathers. I gave them a good bath, and will do so again in a week, I'm just wondering when can I be sure that they are bug free?