You have quite a challenge with all the different ages and sizes. The hardest will be integrating the small ones, and they'll need to have cover or somewhere to run when chased by the older chickens. Something as simple as a bushy branch tossed into the run can be a life saver for a tyke who needs to hide under something so a big bully can't reach her.
What I do is a bit more work, but it's worked wonderfully for me over time. I create a "panic room" with entry holes just large enough for the youngsters to squeeze through and not the older ones. They can run into this special enclosure, and it can be as simple as a dog crate, to be safe from bullies.
I have a run that is broken up into several smaller pens, and I can close these off when I want or leave them all open so the flock wanders freely through them all. I install smaller pop holes wherever there is a place where a chick might get boxed in or cornered by an older hen. It's like watching a cartoon when a larger hen is chasing a chick and ends up crashing into the fence in hot pursuit of a chick who has learned to navigate all the small pop holes.
So that all the new comers get enough to eat, it's extremely important to have lots of extra feeders because the older ones will zealously chase them away from the feeders. This is why a panic room works so well for the smalls. Their food and water is inside and they know they can eat and drink in there and still be safe.
