I think roll mating or line mating are going to depend on what you get for stock. Say you have a very uniform flock and your only real intent is to keep up diversity then rolling males from pen to pen would do that. But in the real world there is a lot that needs fixing or tweeking in any given flock. That's where line breeding and in a very real sense that means inbreeding comes into play. The need to strengthen a trait will often be done with father daughter or the reverse mother son pairings. It's not a bad thing at all. As stated earlier it's the multi generations of very close genetics can rear it's ugly head. It does it in two ways- first the close breeding will allow more recessive genes to pair up. This can strengthen traits you want and can also strengthen traits you never want. With careful selection of breeders and test matings things will go in the right direction. The second way close genetic breeding goes awry is after decades the flock will lose vitality. Everything else is improved but that lack of diversity will reduce hatchability and fertility. That takes a very long time- decades of closed flock.
I'll attach a sample of line breeding diagram. In viewing it you see the typical 4 to 5 generation breeding. As someone said earlier three pens will give you more longevity to a closed flock than two pens. The principle is the same. Your selectively breeding each group for generations then moving a male to the next group. Line breeding again for generations then moving male to next group. Say you set up three breeding pens- A, B and C. Each pen could be line bred for 4 or 5 generations then A cock to B pen, B to C and C cock to the A pen to start another round of 4 or 5 generations. That could be continued for your lifetime. As for management you really don't need to house all your birds in these breeding pens all year. If you don't mind having a constant supply of chicks over the summer then you'd not even need to have three pens. One breeding pen where you moved the breeders into it, collected eggs to hatch then moved another group in. With banding of birds, wing or leg, you know parentage by keeping records. You could have a batchelor pad and a layer coop. Select the breeders you want from layer coop that are from group A and the cock from group A and put them in the breeder pen. Later in spring/early summer move them out and select breeders from group B then in late summer breeders from group C. With leg bands you know who came from what and in small selective pairings or trio or quad breeding you've selected the best to move forward. It's not to advantage to breed every bird.
