Have you heard of the "lethal gene" that some seramas carry. It is what causes the chicks to die right before hatching. It is mainly carried by short legged seramas. The first seramas I bought have very short legs and while I like the way they look, it is bad for breeding or showing. For this reason I am not breeding them. I have bought better quality breeding stock. If you go to the website at
www.malaysianseramabantams.com/lethalgenetics.htm it explains the situation in detail. You are lucky you got 4 pullets to 1 cockerel--out of my last 12, I got 3 pullets and 9 cockerels. Good luck with your next hatch!