Ah gotcha. It doesn't look serious, so I'd stick with what I said previously and just make sure it's disinfected and healing well, that the other chicks aren't picking on it. Vetericyn is safe around eyes, iodine you'd want to be very careful where you dab.
I would use an antiseptic spray like Vetericyn or diluted iodine for most general scrapes and ouches. But the picture isn't very clear where the injury is?
It depends on the State, I think.
https://www.nasda.org/about-nasda/state-agriculture-departments/ has contacts for all the departments I think; they should be able to answer questions about poultry.
https://www.ecfr.gov/current/title-9/chapter-I/subchapter-C has the rules about transporting...
Transporting chickens: you want something that they can't escape from, can't attempt flying in, can stand and move in comfortably, with no way to get injured from stabs or cuts, in a well-ventilated place and protected from drafts/chill/rain. Not in the trunk, and not in blasting hot sun, with...
Possibly a feather grew in very wrong? It's a little hard to tell from the pictures but it looks like there might be some feather shafts glued into that mess. I would try giving her a bath and seeing if you can clean the wound up enough to tell how deep it is and get the feathers out as much...
I would keep poulticing and using boots if you can. If you've used those antibiotics before in their full course to little or no effect they might be completely useless for this.