while you have them caught one day, check their oil ducts to be sure there is not a problem there. Being that multiple birds are doing, probably not, but it never hurts to check while you are holding the. its located in the center of the lower back, where the tail meets the body. Just look to be sure it's not showing any signs of infections or problems. It also helps for them to be exposed to swimming water daily as that triggers their preening instincts. a week or two without it can make a difference believe it or not.
Good luck
Good luck