I'm VERY glad to hear you rescued this pair from people that didn't need birds in the first place! Since they were obviously treated bad, give this pair extra time to seattle in and get use to there new ( and caring ) home. The extra preening could be from dry feathers. Do you give them spray (bottle) showers with lukewarm water? That helps a lot. Although it's expensive, you might consider taking them both in for a vet check up since I doubt either one has ever seen a vet.