I can't comment on Eclectus' specifically, but in-general when you're dealing with an elevated WBC level and then specifically an elevated Monocyte level, AND the bird is a chronic sufferer of a Feather-Destructive Disease such as the bird being aa chronic, continual Plucker, then in my own experience (which is quite a lot considering that over 50% of the parrots surrendered or dumped at the Rescue are Pluckers and/or Self-Mutilators) the very next step is usually taking several different swabs of the external skin (one from each of the major areas of the body) and first doing simple Microscopy (Gram-Staining, followed by other Staining to rule-out other specific Bacteria, Fungi, and other microbes and little buggers), because 9 times out of 10 the bird is currently and probably has been for a long time suffering from a Systemic Fungal Infection, with or without additional Bacterial Infections (though usually when the bird is diagnosed with a long-time Systemic Fungal-Infection and has been a Plucker/Self-Mutilator for quite a long time, most Bacterial Infections that are also found externally are secondary Bacterial Infections that are being caused by the continual Feather-Destructive Disease and not part of the Systemic issue(s))....
****Though I haven't had much experience with many Eclectus' suffering from Feather-Destructive Diseases, I would have to guess that much of the time even the best CAV's and Avian Specialists are going to be thrown a "Red-Herring" due to their extreme Dietary/Nutritional sensitivities, and a lot of the time I would guess that as soon as they see an Eclectus who is a plucker/self-mutilator they automatically ask the owner what their regular, daily diet is, how long they've been eating it, etc. And since unfortunately we know that many Eclectus owners don't even know that their birds have any special dietary needs when they first bring them home, I'd have to bet that the situation is complicated even further when the Vets hear what the Eclectus is being/has been being fed daily (and often when a first-time parrot owner adopts an adult Eclectus that is being "Re-Homed" on places like Craigslist the person who is "Re-Homing" them doesn't know either and has thus been feeding them a horrible, junky all-seed diet, or a fruit-flavored pellet staple like Zupreem Fruit, along with all kinds of other food that an Eclectus shouldn't have, at least not on a daily basis)...So they see an Eclectus that is plucked and is either otherwise completely healthy (throw-in an occasional episode of "toe-tapping" or the like and it gets even worse) or that has been occasionally having some GI-upsets/runny droppings, etc., and they automatically go with the diagnosis of an Eclectus who has been eating an improper daily diet and has suffered from long-time Feather-Destructive Disease as a result...And then they prescribe a complete diet-change, which is done gradually over-time, etc...Even if they run a Fecal Gram-Stain they typically aren't going to see a lot of Yeast, they'd have to send-out a culture to a lab for it to be grown-out, which probably isn't done aa lot in this situation...And I'd bet that when it comes to an Eclectus who is a long-time plucker and who they've confirmed isn't being fed even close to an appropriate diet, they aren't taking many external skin-swabs and sending them out or even looking at them under their own scopes...So I'd have to guess that this isn't caught a lot in Eclectus' who are pluckers UNLESS the bird is also displaying other signs/symptoms of serious illness like chronic vomiting, loose/runny droppings all the time, bright-yellow liquid being passed with the droppings (indicating Kidney and Liver issues), finding placque in the mouth/throat or in a Crop-flush, etc...And in the meantime the topical Yeast (and possibly other strains of Fungi that we don't often take into consideration) is simply allowed to grow and spread and eventually become Systemic...
That would be my guess, as opposed to a Viral Disease such as PBFD, ABV/PDD, etc., simply because, and correct me if I'm wrong since I've been out of the loop for the last couple fo weeks due to my own injuries, but I don't think that Lincoln has been displaying any of the classic signs/symptoms of any of the Viral Diseases, has he??? I mean, has he been displaying any Neurological symptoms? And as far as Psittacosis, the very first symptoms in the beginning-stages are usually Conjunctivitis in both eyes with a lot of discharge (both clear and yellow/green/brown from both eyes), along with Upper-Respiratory Symptoms like coughing, wheezing when breathing, open-mouth breathing, discharge from the nares, etc. So I totally agree that it doesn't at all sound like Psittacosis Chlamydia; I've not ever seen a bird positive for Psittacosis who wasn't actively-sick with at least coughing, wheezing/crackling when breathing, and Conjunctivitis with discharge...
Did they confirm that Lincoln has an external/topical Fungal Infection on his skin/in his Feather-Follicles? If so, then I'd put my money on a bad Systemic Fungal Infection all the way. Not only is it extremely common, but it's also probably the most-commonly misdiagnosed illness in parrots with Feather Destructive Disease...Usually the treatment ends-up being a combination of a long course of the proper Anti-Fungal(s) combined with an Anti-Anxiety medication (Haldol seems to be the most-effective with the least amount of negative side-effects by-far), and after the bird finishes the Anti-Fungal(s) and tests completely negative for any Fungal Infections anywhere (both topically and in their Fecal testing) and their CBC comes back as normal, THEN they start a gradual taper off of the Anti-Anxiety medication, so that not only is the Fungal Infection completely cured so that there will be no more physical reason for the bird to keep plucking itself, but the pschological element of the Feather-Destructive Disease is also eliminated...
