I try not to interfere as much as I can. I’ve always had a good success rate with my incubator and mixed results with hens. I hatch chickens, turkeys, ducks and geese. Recently (yesterday) mother hen was hatching her chicken eggs and decided part way through as she had two chicks to leave the nest. The eggs were cold BUT one zipped and two pipped and STILL chirping to my amazement. I can’t help but step in. Luckily I thought I have a broody brooding shavings. After a few hours I checked on progress as was concerned as the membrane going cold can shrink wrap the chick. The broody had crushed two little chicks and the other pipped one was still peeping but no progress at all. So out came warm water, cotton buds and tweezers. Slowly I moistened the showing membrane and started to peel back the shell moistening membrane as I went being so careful but working as quickly as I could. Then out popped a little chick still with strength!. I tried it under the broody but she was nearly crushing the poor thing so whipped into the house with it down my top to keep warm and whacked the incubator on to warm up so I could dry it off. Chick is now doing very well, currently under a electric hen now nice and fluffy. Has fed and drank. In the dark tonight I will hopefully get it under mum and her two chicks back where he/she should be. I’ve done this on occasions with incubator hatches but it’s rare. I think in my opinion if it’s stuck in the shell and in a incubator it can be because we have already intervened with Mother Nature artificially so I will help if I can. On this occasion it was my hen leaving the nest that caused this issue so I chose to help.