I've struggled with the weight on the males of all the breeds I've kept. I like to read old poultry publications that are in the public domain on the internet. I wish I remembered the source but one of them advised choosing the cock with the biggest frame, and the hen with the most muscle. The theory being obviously that some of the offspring will get the male's big frame and the female's muscling. I haven't tried it but it intrigues me. One thing I have tried which I do think helped was to separate the pullets and cockerels as soon as you can tell them apart. I suspect this would be very early with SGD. Many people already do this but I was growing them out until I had to separate them. Apparently it delays the maturity of the cockerels to separate and they grow bigger. It creates less drama for all of them for sure.