Okay, any update on EVERYTHHING you've fed him the past two weeks? And I mean absolutely EVERY. SINGLE. THING. I don't have an eclectus, but I do have budgies who have been projectile vomiting everywhere and scratching their vents half to death due to food sensitivities.
Here's what I'd completely cut out:
• NO ROOT VEGETABLES! Especially no sweet potato, okay? It takes three to 14+ days for my budgies to react to sweet potato, but when they finally react, there's vomit EVERYWHERE. Poor Ju's face was covered in vomit, and he aspirated on it (he's fine now, but it looked like he was dying).
• No pulses. No peas, lentils, mung beans, Pinto beans...nothing.
• No green beans, yellow beans, etc.
• No seeds. If you want to give him seeds, give him organic sunflower seeds.
• Absolutely no cherries or berries. I remember one of the members on here talking about how her ekkie started TT/WF from cherries. As for berries, I personally react badly to them. The berry sugars cause severe heart palpitations and maybe a sugar rush, which causes me to have a full blown anxiety attack for more than 8 hours.
• No really sweet fruit (no pears, pineapple, plums, etc.)
• No egg, meat, nuts, or quinoa. Well, actually, maybe feed him egg whites, and not the yolk, since we don't need him to pass out due to lack of protein.
• No pellets
• No corn
Here's what you can try (all organic!):
• Squash and pumpkins (cooked; starch is our enemy)
• Romaine, dandelion leaves, chickweed, clover (wild), shepherd's purse, eucalyptus (not from florists), bottlebrush, purslane, mustard leaf, Swiss chard, peashoots, beet leaves, turnip leaves
• Grass seed (collect fresh grass with seed that hasn't fully ripened yet)
• Chamomile and lavender from a health food store (food-grade) in a dish, available at all times
• Hibiscus, lilac, nasturtium (food-grade)
• Melon (including a small number of melon seeds, along with rind)
Just a heads up, it takes Samantha at LEAST two weeks before she shows symptoms! My poor girl's been suffering because I kept ruling out the mash as causing her tummy problems, but that's because it takes at least two weeks for a food to cause her problems, and at least two weeks for her to completely get it out of her system.
You should be sprinkling powdered eggshell on his food at least once a day. Boil the eggshell, wait for it to thoroughly dry, then stick it in an immaculate coffee grinder.
As for root vegetables, do not give him any! Sorry, am I yelling? Anyways, I think it's the starch that my budgies don't react well to. Root vegetables would be one of the last things I'd try reintroducing. Pumpkin is far easier to digest than sweet potato. Again, you want to feed Jasper low starch, low carb, low sugar foods.
The lavender and chamomile flowers are used pharmaceutically by my birds to lower anxiety and stress. Your boy might benefit from them as well.
Look up "eucalyptus herb". Buy unadulterated dried eucalyptus leaves/twigs for him to nibble on (I had a couple of eucalyptus trees growing last year, but Mom let them die while I was away for a week). Also consider buying "Now" eucalyptus oil. Put a couple of drops in a glass or stainless steel dish, add water, and let him bathe and drink a bit of it. I recently started doing this for the budgies and kākāriki, and they seem quite attracted to it. Jasper, being an Australian species (probably), might benefit from eucalyptus.
Also, he might benefit from a poultice applied to his feet made from greater plantain leaves and cayenne (sounds weird, but just try it). Beforehand, try having him soak his feet in warm water for a few minutes to promote circulation and open up his pores (do birds have pores? I don't know), then apply the poultice.
You can get dried dandelion at the healthfood store. You can buy organic mixed greens at the grocery store (they're sold in plastic containers).