My bantam orp was once bred by a LF orp cockerel. (For some reason the teen roosters always give poor Cookie a hard time. ) Only the one time were her eggs fertile, and all the other times I set her eggs they were clears. The one resulting chick/pullet was slightly smaller than her LF siblings but not a bantam. Her owners say she inherited Cookie's strong broody instincts. I never had much luck when bantams and LF attempt to breed. The bantam hens are faster and stay clear of the big boys. Same goes for the lighter breeds like Leghorns vs. Orp roos. Once the boys are mature enough to handle the LF hens, they learn to leave the bantams alone. My serama roo (16oz) may attempt to mate an orp (9lbs) , but it's more entertaining. The big hens eventually get annoyed and chase him off. @homeschoolin momma may have had some success with her serama. I know she had a few surprise spitz x orps.
Genetics of course play a big role in size. But, I find the age of parents and nutrition also has a lot to do with size. Pullets tend to have smaller chicks. The same breed hen will have bigger chicks. Feeding chicks a quality feed with a bit more protein tends to make them grow bigger (or maybe faster). This is more anecdotal. I grew out some chicks with turkeys and all ate meatbird feed. They seemed slightly bigger than other batches, but I never actually tested, weighed, and measured them to compare. Could be an interesting sci project.
Genetics of course play a big role in size. But, I find the age of parents and nutrition also has a lot to do with size. Pullets tend to have smaller chicks. The same breed hen will have bigger chicks. Feeding chicks a quality feed with a bit more protein tends to make them grow bigger (or maybe faster). This is more anecdotal. I grew out some chicks with turkeys and all ate meatbird feed. They seemed slightly bigger than other batches, but I never actually tested, weighed, and measured them to compare. Could be an interesting sci project.
