I am ordering some Jumbo Peking ducks from McMurray. I want to keep a couple hens and drakes so they will continue to lay fertile eggs in the future so I don't have to buy more. Here is the question...What is the size difference between the boys and girls? If I'm looking to buy the first round and keep 2 boys and 4 girls to continue the line....what should the rest of my order be if they are going to be meat birds? If it were chickens...i'd say boys but the girls are pretty big too. Is it similar to the chickens i raise? I've heard 8 weeks to harvest...really?