Well, It's been about 4 months since I last posted, so I think I'll post an update. But really, nothing much has changed since last March. It's now late summer. All 3 birds are doing fine, they are healthy and active. But neither of the hens has shown any interest in mating or breeding. They've never gone into either of the nestboxes, or shown any curiousity about them. The white bird I think is a bit over a year old now. He still has a pale pinkish/blue cere, and I don't think it will ever turn bright blue. But it acts just like a cock. It approaches the hens, bobs its head, and acts affectionate toward them. They sometimes do seem to respond a little, but then they fly away. They don't seem to have any interest in mating. Both hens have dark, crusty ceres, and they seem to be in good breeding condition, but lack any interest.
I will just have to be patient, and let things take their course. I keep the parrakeets in my bedroom, and have no room for an additional flight-cage, or for any additional birds, so I'll stick with the 3 birds that I already have, even if they're not inclined to breed.
They get a good commercial seed mix, with some pellets mixed in. I give them greens (dandelion, plantain, lettuce) or fruit (apple, pear, orange) each day, and they have a mineral-block and cuttlebone.
I'm still trying to learn how to post photos with the iphone I acquired last years. As soon as I can, I'll post some photos.