@Epiphany How old? Is she shaking?
Chicks DO have a mortality rate, lots of things can go wrong when developing in the egg - that’s why momma lays fifteen at a time.
My lady has spent many nights carefully feeding a wonky poult with a syringe full of raw egg yolk. When we have more than a couple hatch at the same time, she hardboils them and minces up the egg to feed them, probably the best intervention to date.
Also coraid, apple cider vinegar if you have the watering systems running for a long time. Easy for their poop/water to start breeding nasty stuff.