I have a baby Delaware chick that had the exact same symptoms as you're describing. Could walk ok in stretches, but soon started to wobble a bit, and when it laid down, it kind of 'flopped' to one side.
I considered taking it out of the general population and giving it some time, but none of the chickens aggressively attacked it for being weak, and the chick still wanted to be social - and as you know, the noise they make when they can't see their other chicks is funny when the chicks are just around the corner, but it's kinda heartbreaking when they're truly isolated.
We keep two water sources in the pen, one for just plain water, the other is a vitamin water. So to make sure the chick had the best chance, we put both water sources with vitamins for a week and it seems to have actually worked. I checked on the group last night and the chick was up and running, full speed, with the rest of the pack. No wobbles, no flopping.
Not every case is handled so easily, we did lose one chick early this spring - it just didn't seem to thrive like the rest and passed away. But sometimes a simple fix is all that's needed. Good luck to you.
