That humidity isn't a problem, but I keep mine between 40 and 50 the first 18 days then raise it to 65-70% the last three. I know my issue had to be their molt/nutritional needs since most chicks hatch clean and with basically no cleanup, no rough navels, etc. So my humidity was good. Some feed lines have breeder crumble/pellets. Southern States has Super Breeder Crumbles, for instance. I currently use Game Bird Breeder Crumble from Purina's line, 20% protein, made just for hatching chicks. My Blue Orps are molting, but still laying and I'd never had an issue like this before, except once. My Barred Rock hen, Lexie, was naked from molting for literally months AND still laying almost the entire time. It was during that time that her usually very vigorous chicks weren't hatching that well. Dont help till they've pipped the shell and been at it for a good long time and it's clear they will not be able to make it out. It could be Day 22 even. Just let them try to get out on their own. No, I would NOT help on Day 19! You're asking for trouble if you do that, trust me.