Hatcheries sell chicks in groups of straight-run or pullets. Straight-run is a mix of genders. With a straight-run group, you take a gamble of having just as many, if not more, males than females. Pullet is a term for female chicks under the age of one. You may find it beneficial to pay more for a group of pullets. Keep in mind the guarantee percentage for all females in a pullet group is high, but not 100%. There is a chance your batch could have a rooster.*
The majority of The Mill’s chicks are pullets.
The Mill’s French Guineas, Ring-Neck Pheasants, ducks and turkeys are straight-run.