Thank you for the info, people. Now, to answer a couple questions. The lamp is 'just a random light with a bulb I found' in the garage, yes. It's one of those clip on lights, for working on cars. Pardon for not having a proper heating lamp made for chicks and such, but I'm using what I got. And the lamp seems to offer plenty of warmth. I always check the heat, make sure he isn't getting too warm. But it's been perfect, I'd say. And I'm not giving up on the feed so easily. I'll be going myself, and yes, Unmedicated chick starter feed, got it.
@CollegeChicken, I only inquired about gathering food he would eat in the wild because, hey, where's he gonna get Unmedicated starter chick feed in the wild? It was worth a shot to see about his natural diet. I hope you're not under the impression that all I've been doing is snapping Cute photos of kittens and ducklings. My days are quite full. I'm not looking to have him rehabilitated into the wild, and I don't know of any professional rehabilitators, sorry. I tried eggs with him, he didn't seem all that interested, alas. But I'll try again.
As for grit and digestion. His little outdoor environment has it all, he's often pecking at passing buggies, and I've seen him get down into the dirt. He's not constipated, and he's not experiencing diarrhea. I'd say his poops are normal. And he's got a healthy appetite, he'll eat enough, and when he's full and content he'll go about his other activities. Grooming, exploring, etc. He doesn't over eat, but be does eat enough. And he drinks plenty of clean water, I always change his dish and 'pool' tray.
Again, thanks for the info and advice.