I hatched some eggs from a mixed flock. Several types of hens, but predominantly white leghorn. 3 or 4 differnt choices for the dad. I ended up with 1 little black chick & 4 white fuzzy cuties. They are 3 weeks old now and 1 of the white oneshas a comb that is significantly larger than the others. Is it a safe assumption that it's a rooster? Are there other qualities I could look for in such a youn chick?