I volunteer at a wildlife rescue and have taken in baby starlings, but released them. I'm very against keeping wild birds as pets. They do not imprint, but they are very piggy and will eat and eat, and quickly can "train" you to feed them constantly. You don't need to feed them every time they want to be fed, but should eat every 45 minutes. Keeping a wild bird captive is just plain wrong, IMO.
I didn't read what you are feeding, and it looks like you've got some knowledge about caring for them. They look healthy. Where are you hearing they have some illness? Are you feeding "Exact"?
I agree with you that wild birds don't make good pets....However I had no clue what to do at the time, and the birds were in a barnyard with 20+ cats, all there for their mousing skills....one bird was caught by a cat but I pulled it out of its mouth.
Wildlife rehabbers all around me are NOT accepting Starlings to rehabilitate.....they cause huge problems around here, and you're right, they are very piggy. They destroy native populations, and disturb the birds around here. They do bother nesting birds in birdhouses, and they also invade bird feeders. A few times each year we get a flock of 1000+ starlings, and they go from yard to yard and completely clear the place of bugs and scare away all other birds. The only person who would take the birds is my uncle, who lives right down the road from me. But I know that his specialty are birds of prey (he used to have hawks, falcons, etc) and he was trying to teach me about feeding the birds and such, but it was all wrong information. He wouldn't be off much better than I am.
When I first found them I thought it would be OK to give them worms, so of course the unknowing me was at a horse stable, and since the soil was healthy, along with the rainwater and fertilization, I thought the bugs would be healthy. Each chick got about 2 worms chopped up.
I read on starlingtalk.com that they should NOT eat worms, and I looked up "Gapeworm" from there....
Last night I was holding the chicks in my lap while watching tv, and one bird was sleeping, the other was begging for food. Well, I noticed the sleeping one was shaking. I thought he was just shivering so I covered him with my hand and cloth more. Well, his head started shaking more, as though there were something bothersome on it. Then he opened his mouth about 1/3 wide and stretched out his neck, apparently gasping for air. I got worried so I put them back in their "nest"....I put my head right next to the sicker bird, and I listened carefully while he gasped. There was a faint "haaargh" sound as he gasped.
Lots of websites did say that those were all classic signs of Gapeworm....also I notice that when I feed the babies the sickly one stops eating about halfway through, then opens its mouth halfway and acts like it's begging for food, chirps, then refuses food when I offer it.
Another problem is that they have mites. Starlingtalk.com says that the mites are species-specific, so they won't transmit to other birds. I have 2 parakeets so hopefully they'll be safe. They were in the same room lat night, though. Both starlings are itching, but only slightly. I'm stopping over at Agway (farm supply store) and I'm going to get some kind of horse wormer....I read online that Invermectin is a good ingredient in horse wormer that will kill gapeworm if fed to a chicken....however, even a smudge might kill a starling, I'm guessing, because even though the percentage of Invermectin is about 1.87%, that might be too high.....Someone said to smear it on the animal, some say to feed it.
Anyway, what I'm feeding is basically a mush that I completely crushed using a mortar and pestle...I mixed applesauce (starlingtalk.com said to add that), high-protein canned dog food, Blue Seal adult cat food (high protein), cooked chicken, hard-boiled egg, and pulverized egg shell. Someone suggested to add crushed cuttlebone for calcium, and I have plenty of that but I'm not too sure about that.
I'm not feeding any store-bought bird formulas because I read that they aren't for birds like starlings....and on kaytee.com there is a warning that says "recall on Exact Baby Bird Hand Feeding Formula" which doesn't sound very good. Anyway, I appreciate your concern for the birds, and I'm hoping to hear back soon.
(Sorry for the long post....when I type, I type a lot)