I had this happen with the one broody I've let set, who hatched in a frigid Feb, I was able to 'save' chick because I had gotten broody used to me touching her and peeking under.We put her down to carefully inspect the situation, and her down was wrapped around their necks! We carefully had to trim it off her and then pull it off the chicks... but we are super lucky we found them because they would’ve been strangled!
Best of cLuck on the rest of this hatch!