I will be putting some eggs in my incubator in a couple of weeks for the first time. I have Heritage RIR rooster and hens. Is there a way to tell within a few days if they are males or females or will need to wait until they grow some. When I purchased my original ones from the local hatchery they were 4 days old and I was new to this. I wound up with 10 roosters and 2 pullets. 
