Mine came out all full of goo and I had to wash him gently under just warm water and then put him in the brooder under the light to dry and she was just fine. I don't know why it was so gooey other than maybe too high of humidity or too low, not sure which.
I had the issue with my chicks, every single hatch but the first one. In my experience it seems to be worse with a higher humidity during hatch, especially since when my batch of 13 hatched, it got progressively worse towards the end of hatch.
The batch of 4 after them, the very last chick to hatch looked like ducky, like he had gone swimming in hair gel and it dried. He hatched something like 26 or so hours after the first chick, and didn't even pip until after the 3rd was fully hatched, but he was the 1st internal pip. He was very exhausted from his hatch, and would only move when a hatchmat used him as a parkour prop, so when I took them out, he didn't move, just slept. He'd pick his head up every now and then, but that was it. That experience led me to think the less active after hatch, the worse it is too. It seems like as they move around, it breaks the hard gel and let's them fluff up. If your familiar with curly girl method, scrunching out the crunch basically. It also took him a full extra day to realize if youre thirsty, drink, if your hot, don't sit directly under the heat lamp. He would be panting hard in the brooder, and if I moved him and dipped his beak, he'd take a drink, then crawl right back under the heat, to again be used as a parkour prop.
What I'm pretty sure happened here, is with him having been open for so long and the fan, and maybe the cup trapping and directing the air flow a bit more, his down completely dried while he was in shell. So it hardened, but since he wasn't moving, it never started to break apart. A very soft toothbrush is working pretty well for now, he's mostly fluffed up. With all the stress I've already put him under, I'm not keen on the idea of washing him off just yet and then drying him. If there's no better choice, I will, but so far "pretend" brushing him is working