If the bird can eat greens, it needs grit - you don't want to see a crop full of impacted grass and no way to grind it up.
That does give you options. You can feed a higher protein feed to your meaties, to speed weight gain, and a lower protein feed to your layers, after they reach point of lay (if desired). Or you can keep them all on the same 18-20% protein all flock type feed. If you had lots of layers, and few meaties, it would probably be worth the cost savings to do seperate feeds. With mostly meaties and a dozen layers, probably not worth the hassle.
and
@Weeg 's Scratch and Peck recomend isn't a bad one. They have corn-free, soy-free options, they are national in scope, stocked some places, can be ordered elsewhere, and are decent quality. Because most of their feeds are whole grain, you will want to soak them for hours to days before use, to help deter birds from picking favorites and leaving the rest for those lower in the pecking order. It is hard to find higher protein (20%+) Scratch and Peck options, but you might consider supplimenting their feed with a measured, SMALL amount of flax seed (not more than 10% by weight) - meaties can take a slightly higher fat diet, since they aren't intended to live long - the bet is that you gain more in table weight on average, and more rapid weight gain over all, than you lose to diet related morbidities. Targets for CX are 20-24% protein, with fat from 4-6.5%, as compared with 18-20%, 3.5% +/- (respectively) for the "typical" chicken.