Another update, for reference in case somebody finds this someday who is having a similar problem. Got bad news, good news, and a professional diagnosis this time:
My buff orpington chick who had this problem... and got better... started gasping again last night. I gave her the same treatment that worked last time - gatorade, and a quiet dark place alone. She seemed somewhat better by morning but was still gasping a little.
I've grown very attached to this one now, and to another one that has a gimpy leg, and they both think I'm mamma. I bought these chicks and 48 others from a hatchery in Missouri, and fully 1/3 have died of this problem.... gasping, wheezing all of a sudden, then within hours getting sleepy-like symptoms, growing weak, and dying. I didn't have a mass die-off, over the first 3 weeks it was worst, and I was losing 1 chick a day, sometimes 2, sometimes none. I lost 16 chicks to this problem. On the other hand, I have 12 new babies I got from a farmer in Missouri 1.5 weeks ago, and they are fit as a fiddle and never had a problem, not one of them has had a problem. I manage them the same way, feed and house them the same way, but they've been kept separate, so it's not what i'm feeding my birds or anything I'm doing that's causing the problem.
Since she was still gasping a little this morning, I got fed up... the wife is very attached to this one too, and we decided to go to the Animal Medical Center in Pittsfield, IL and see Dr. Wilke there. He was VERY nice, if any of you are in the area go see him when you have chicken problems, definitely. His diagnosis is....
A bacterial pneumonia problem. It is *not* brooder pneumonia like I thought, according to him, since it is bacterial and not caused by a mold or fungus.
He said it's possible the illness came from the hatchery, but may have come from something else too, one of the chicks may have been a carrier, etc. I also told him that I'd given them Terramycin for a while and it didn't get rid of the problem, and he said sometimes it wouldn't (for reference for someone in the future who might look up this problem). He gave me a tube of some pink antibiotic stuff, I didn't catch the name of it but he may have said it's a sulfa drug, not sure. I give the chicks 1cc of it per gallon of water for the next 5 days and he thinks the problem will disappear. "Lillly" the chick,should make a full recovery. He also gave her an oral while we were there.
In addition to this, he also checked out my chick with the gimpy leg. He said he didn't think it had been broken, and thought it might be a pinched nerve, and gave her a shot.
Cost for two inspections, one oral medication, a shot, and a tube of antibiotic for my other chicks? $20 bucks. I coulda kissed the guy, almost told my wife to!
So if anybody has problems losing a chick or two a day... but not having the others get sick... symptoms are gasping/wheezing to start with, and later very labored breathing, getting weak and sleepy, and dying... your problem may be bacterial pneumonia, and terramycin didn't cut it for treating my birds.
Hope this helps somebody someday to avoid the losses I had from this problem! If I'd known the Vet wasn't going to cost a hundred bucks I would have went out there much sooner, but I'm still used to Los Angeles prices I guess.