Judging by the pic, they are about 3 weeks old? If so, roo vs hen behavior has probably not already started and boys and girls can be equally as picky and mean. Cali whites are just like leghorns, some with more black feathers than others. If all have the same conformation, except barred feathers, you may have a cali grey. If all white, may be leghorns. Either way, these breeds are all a bit flighty and I find mine to love exploring and getting into trouble. Seperation is a good thing, 2 roos and 4 pullets = lots of fights between roos when they reach "puberty" and beyond, and in addition, if the one boy who is top or is kept has only 4 girls, he may make his favorite one go bald on the back due to over maiting. In a week or so, the boys will start to show reddening of the combs and wattles. For sure by 5-6 weeks you will be able to see boys vs girls.