I usually had one chick in each batch with this condition, but this batch I had 2 so far. The chick will hatch covered in a gooey yellowish substance, when it dries it’s very hard to get off and pullling it off really hurts the chick. I’ve had chicks that let this substance dry when hatching so that they get stuck to the egg and never even make it out. I’m pretty sure the substance is coming from the egg sac but I have no idea. It’s probably an incubation/ humidity issue but if you know what this is or how to fix it please let me know I’m desperate!