I've been breeding and raising chickens for a year now. I breed primarily Silkies, but I've also started breeding Booted Bantams and Red Golden Pheasants, when they're in season. For the better part of the past year, I've been giving my Silkie girls small hatches with about 4 or 5 eggs, and usually 3 or 4 are fertile and hatch. I did this so my hens could get experience raising small hatches before giving them larger hatches. The only issues I've had with chicks dying mid-hatch or dying after developing almost fully is last year, when I was having diet issues with my Pheasants and the chicks didn't have the strength to survive after hatching. Otherwise, every egg that was fertile was growing and hatching just fine. But, I've been increasing the hatch size, and I've also been encountered hatching issues. Now, depending on the availability of fertile eggs, I usually put 6-9 eggs under my Silkie hens. I first encountered issues with the egg shells of the already hatched chicks going over the eggs that haven't yet hatched. I guess this started happening since more eggs = more egg shells = more of a chance the egg shells will cover the other eggs. Being unable to break through two layers of eggs, the chick in the egg dies. I first thought this was just a freak encounter, but after losing a few chicks to this, I decided I should start removing the egg shells every few hours while the eggs are hatching. I do that now, but now I have issues where the chicks will pip, but after making the hole, they never progress after that and die in the shell. Is this because I'm having to lift the hen(I don't remove her, I just lift her up some) to remove the egg shells? I know with incubators, it's extremely important to keep the incubator closed during hatching, but before I started removing the egg shells, I would still have to briefly lift the hen to periodically check on the hatching egg's progress. This has only happened a couple times, but it's worrying that it's happened more than once after going a year without incident. The hen's diet hasn't changed, they nest in the same area, etc. The only thing that's changed is that I've sold my old roosters and got new ones(but these roosters had fathered healthy chicks before). I always open the egg of deceased chicks to examine the body for abnormalities, but these chicks don't appear to have anything wrong with them. No abnormalities, no blood, yolk sac is completely absorbed, etc.The pipped area is in the appropriate place and looks clean. I've raised doves for the past 8 years and I was under the assumption raising chickens would be fairly similar. Turns out, they're VERY different. With doves, if the egg is fertile, it's gonna hatch. If it's not, it won't. End of story. With chickens, even with using broody hens, everything has to be precise. Just as you start to think you know what you're doing, something else happens! Can somebody tell me what's happening, if these sudden deaths are unfortunately normal sometimes or if I'm doing something wrong? Thank you!