Feather loss is one of the most frustrating things a bird companion faces. Sometimes we can spend thousands of dollars and years looking for a cause, then, one day, it just resolves! In a large number of cases though, it's a permanent feature of a bad habit.
Some birds start plucking or losing plumage because they have some sort of parasite infestation, either on them or in them. For this reason, you need to have a full medical eval by an experienced avian vet who knows what to check for. There are no home treatments and those treatments you see in pet stores? Leave them there. They are a total waste of money and time - and can cause serious health complications in birds. I wish they were never sold.
Nutritional problems – lending to liver problems and that by itself is a cause of feather plucking.
Nutritional issues accounts for up to 90% of feather plucking & feather loss problems according to some published veterinary medical studies and research. Some feather plucking that begins as the result of physical cause such as this or any one of those mentioned above, may end up a ‘habit’ – and once it’s a behavioral issue, it’s even more difficult to stop.
Once organic/physical cause is relatively ruled out, you can try to modify the behavior with various environmental changes. Sometimes it's as simple as the lighting. Try replacing fluorescent bulbs with full spectrum bulbs or at least try a different (newer) brand of fluorescent. Birds see at different wavelengths than humans and there may be 'flickering' perceived from a fluorescent bulb that drives them to frustration - which leads them to plucking.
It will also help to distract your bird when they begin over-preening. Get them engaged in learning something new, even simple things like shaking ‘hands’ or introducing themselves.
You don’t want to stress your companion though, so don’t push the learning if they aren’t up to it. Just take them out of the cage and spend time with them. Talk or watch t.v. – all that matters is that they are not getting carried away with the preening.
It will take several weeks to see the difference (about 2 ½ to 3 months), but since that time will pass anyway, it’s worth making the effort.
For more about the right nutrition for healthy feather and an overall happy bird take a look here www.4Animalcare.org/birds
Sleep deprivation may also contribute to this (and sometimes increased screaming and nipping). You may want to try establishing a separate sleep cage in a room that’s quiet with dim lighting - or offer the bird an opaque cover in their present cage, keeping the sounds and activity down in the house while it’s in sleep time.
Birds need 12 hours of sleep time, preferably the same hours every day. For example, if you tend to get up at 7 a.m. every morning, try to put the bird to bed at 7 p.m. every night and make it your priority when you get up (don’t leave them covered/in sleep cages while they can hear you up and about or it will only lend to their frustration and possibly stress levels).
Regular 12 hour sleep hours also help curb mating behavior, including egg laying.
Cage bound and unchallenged birds will self-mutilate. Does it have enough real wood to chew and shred? Enough room in the cage to fully turn around, side to side and upside down without (what would be his/her) tail feathers touching any side? Does the bird have three different sized perches of different materials? Rope perch, natural wood perch and 'rough' perch for nail and beak grooming. Make sure the perch near food dishes and higher up are the most comfortable ones since they will be using it more.
We have our rope and natural wood perches on the same level with the rough perch just a tad down from them.
Does your bird get to spend at least two hours out of cage every day? The average bird owner has their companions out on average for four hours (we found this very refreshing). Ours are out for at least 7 hours.
Back to the subject of food: It sounds like you're doing a great job with the pellets.
A rule of thumb among avian veterinarians is a predominantly pellet diet with seeds, nuts, fresh fruits/vegetables/legumes and grains supplemented daily. We give them whole multi-grain oatmeal with cut up apple and/or banana in it for breakfast every day (just add warm water to the oatmeal, no need to fully 'cook' it) and their mid-day meal of whole wheat couscous and whatever veggie in season (choose the darkest greens like kale, collards, broccoli, etc).
www.spca.bc.ca/AnimalCare/birdcare.asp and www.thebirdbrain.com/html/foodforus.cfm?category_id=4&subcategory_id=22 provide more information and professional nutrition ideas.
Cuttlebone and mineral block are also essential, not just for the calcium, but for the outlet to bite and scrape their beaks.
Keeping the bird misted every few days with warm water (out of drafts of course) is also something that may help. Many birds enjoy sharing the shower with their people :) We'd just recommend that you use only baby safe products on yourself for this shower to reduce any possibility that the bird is harmed from regular soap/shampoo.
Before introducing any new rescue to our habitat, I opt for the full DNA/genetic profile and avian exam. It's soooo worth it! Having this done with your companion will provide incredible peace of mind, or at least determine what the problem might be and you can save yourself a lot of complications and expense.
You can get an idea of the prices here http://healthgene.com/Avian and see that they’re pretty reasonable; however, we strongly recommend that your vet do the sampling, so figure in an office fee accessed along with the testing cost.
Never – not ever – consider using a blood feather to send in as a sample. This can cause uncontrolled blood loss and in some cases may actually lead to feather plucking. I don’t understand why these labs still encourage it and strongly feel they shouldn’t.
So, starting out with a truly necessary vet visit and evaluation is your first step to resolving this issue and I sincerely XXXXX XXXXX bird is better and in full feather very soon.