Thanks. Would you suggest mob breeding instead, and just cull the worst? That was a possibility during the planning stages. I thought doing two different groups would speed up the mixing.
Here's the thing. Assuming you let them all mingle and free range all day, with little intervention when it comes to which bird you cross to who, the results might be undesirable. You might want a good flier and a good mother, but you end up with a good layer and a good flyer, with no brooding in sight (although this exact example is not a good one). Having two separate populations gives you more control. If one of the two lines doesn't turn out like you want it, you've hot a second one on hand