I'll chime-in with the same response, that it is definitely the "molting season", and this year does seem particularly bad for everyone's birds. If you take an overall-look at the forum right now, it is just riddled with posts about molting/pin-feathers/dry skin and the like right now. So if your bird, or birds are losing feathers right now, even in huge amounts including their down feathers, it's most-likely just them molting, which can go on for quite a while, months even.
As Noodles mentioned, when a bird is actually exhibiting any type of Feather-Destructive Behavior, whether it be Plucking, Barbering, etc., they don't do it in a symmetrical way, or in any "pattern" at all. They typically just find a specific area, or multiple areas, that they start messing with and then they keep working on those. When they molt, typically they lose feathers bilaterally, and in-turn they develop the pin-feathers bilaterally...
****A mistake a lot of bird owners make is focusing on how often they are seeing their bird "messing with their feathers", or "picking at their feathers", etc., when 99%
of the time they are driving themselves insane worrying about the fact that their birds are simply preening themselves normally. All birds spend a good amount of time every day preening themselves. That's just what birds do. A feather gets out of place and they preen themselves. They get feathers wet in their water dish and they preen themselves. They fly across the room and they fix their feathers. And so on and so forth. So you'll drive yourself insane if you focus on how often you see your bird preening themselves and mistake it for Feather-Destructive Behavior...
****Instead of watching for how often your bird is preening itself, what you need to pay attention to is the condition of their feathers in-general, specifically at the ends of their feathers. Usually, and I'll repeat usually, birds who are starting to actually display a chronic Feather-Destructive Behavior don't just start ripping their feathers out in large numbers all of a sudden, it's unfortunately (and fortunately) not that straight-forward; unfortunately because it's not that easy to identify as a problem, but fortunately because if you are able to catch the very beginnings of a Feather-Destructive Behavior, then you have a much better chance of nipping it in the butt before it turns-into full-blown plucking...
So, the best way to monitor your bird in-regards to whether or not they are developing a feather destructive behavior is to take a good look at their feathers at the same time each day; the best time being first thing in the morning, as they tend to really go to work on themselves before they are out of their cages and doing things with you during the day. Take a look at the very ends of their feathers for Barbering, which is the act of your bird literally "chewing" their feathers, usually the ends. Usually it starts with the tips of their tail-feathers, the tips of the feathers on their shoulders and at the top-back of their wings near their shoulders, and the tips of the feathers on their legs. If you take a good look at your bird and it's obvious that your bird's feathers in those areas are all "chewed" at the ends, so that the ends look very "choppy" and uneven, and they continually stay that way, even after a molt when brand-new feathers have grown-in and then again the ends are very quickly chewed-up and uneven, then it's very likely that your bird is "Barbering" itself. "Barbering" is a Feather-Destructive Behavior in and of itself, and some birds never progress into full-blown "Plucking" from Barbering, they simply remain chronic Barberers. However, most birds who do become full-blown Pluckers" do start-out by Barbering themselves, OR they display both behaviors at the same time; some will always Barber certain feathers and Pluck certain feathers in other areas. But if you find a few feathers laying in the bottom of your bird's cage or on the floor in one spot and you're worried that this might be the start of your bird Plucking, take a good look to see if there are any signs of your bird chewing/Barbering any of the ends of the feathers in those areas, if not then it's likely that your bird is simply molting, or just preening themselves and they pulled-out a few feathers that were annoying them in some way.
