I've never lived with Eclectus but I've read alot of stories on other sites. The best thing, imo, is to be proactive before any problems start. I would read up on anything written by Laurella Desborough and other experts like the Land of Vos site.
First with vet care I'd establish a good relationship with an avian vet and get yearly tests and check all the basic levels.
Then nail down diet with your vet and other experts on Ekkies. They are different and their diet in the wild is different not nearly the amount of protein that others eat. I understand diet to be absolutely critical to Ekkies.
I'd only use distilled water.
I'd tweak the full spectrum lighting and read about it specific to Ekkies if there is anything online.
I'd enforce a strict, dependable schedule that they can learn to look forward to and enjoy. And I'd never keep them up adhering to our human schedules with late nights and short overnight sleeping schedules in an active room.
I'd try to follow a strict natural daylight schedule including dawn and dusk following the seasons....providing the same amount of daylight hours that is going on outside where you live. If necessary I'd use a dimmer on a lamp placed on the floor simulating the dawn and dusk and angle of the sun.
They have a sensor in the brain (pituitary gland) that controls all hormones and metabolism telling the body what time of year it is. They shouldn't be hormonal unless its breeding season and that's only spring/summer. People always say they adapt but they don't. They just dont have any choice but to adhere the best they can so you get alot of behavioral and health problems and once it starts everyone is focusing on the symptoms not the root cause, imo.
I wouldnt encourage any breeding type behavior by stroking beaks, feet, backs or butts, or allowing regurgitation or nesting in my clothes or other dark or private spaces.
I'd also do alot of enrichment and fun activities where they can learn things that they seem to enjoy.
And of course (being me lol) I would never clip their wings. Not just to prevent Feather Destructive Behavior and psychological problems but to provide the right cardiovascular and muscle development key in fighting Artherosclerosis and other problems they are prone to.
(actually all this stuff is really basic to all parrots but I think it seems really important to Eclectus. Especially diet)
No pressure on anything, though
