I have 5 chicks and 2 are much smaller than the other 3. I am wondering if the roosters get bigger much faster. One chick is 7.6 oz and the one I am pretty sure is a cockerel weighs 10.4 oz (he also has a bigger comb too). At this age of 23 days a difference of nearly 3 ounces is pretty huge. They were all about the same size when hatched.