Could be a number of things. Do you check your air cells to monitor the growth during incubation. If the eggs were from the same breed or laying hen, it could signify that that breed or hen lays either thicker less porous shelled eggs and could be a matter of them not loosing enough moisture during incubation or the flip side of that they could be more porouse and thinner shelled and loose too much. There could be issues with the breed itself in the flock if they came from an outside source. Some breeds such as the Aracauna and Japanese bantams have lethal genes in which 25% of the can die in shell. (I say can because with the Aracaunas it depends wether you are breeding tuft to tuft or tuft to clean faced wether you can get the lethal allel or not.) It might not even be the eggs there's a slim chance that if the same breed of eggs were kept in the same spot in the incubator and it happened to be a cold/warm spot, it could contribute.Oh ok. Can you think of a reason that most of what i lost are all the same breed when i placed such a wide variety?
Blood ring itself is an indication that the egg stopped developing early in the incubation. It can be because of bacteria. I have read the same thing. I believe that most deaths that early are contributed to being because of bacteria, but it doesn't neccessarily mean that's what caused the egg to stop developing.I though I read somewhere that the blood ring was indication of bacteria getting into the egg.