When you say suffocated, do you mean that they drowned in their own egg fluid, or that the incubator had poor circulation and there wasn't enough oxygen at hatch?
Lack of oxygen could definitely cause some brain damage.
If the eggs didn't lose enough weight during incubation, due to humidity being too high, this can cause the drowning.
With posted eggs, the hatch rate will be halved, but if you picked the eggs up yourself and had a smooth ride, there's no reason everyone shouldn't have hatched unless there were problems with the stock themselves.
Did you do any candling on the quitters? Any signs of bacterial corruption, or were the failures for other reasons?
Lack of oxygen could definitely cause some brain damage.
If the eggs didn't lose enough weight during incubation, due to humidity being too high, this can cause the drowning.
With posted eggs, the hatch rate will be halved, but if you picked the eggs up yourself and had a smooth ride, there's no reason everyone shouldn't have hatched unless there were problems with the stock themselves.
Did you do any candling on the quitters? Any signs of bacterial corruption, or were the failures for other reasons?