25 birds might be a lot for that set up, by fall when all are full grown, but I am assuming that you are expecting half to be roosters, and will cull them? That is pretty reasonable then headed into winter. You want more space per bird, cause they spend 14-16 hours roosted up during the short days.
If you want a nice meaty dual purpose, I really like the Delawares I picked up last spring, but they were very slow to mature, nearly 7 months old. And a couple of weeks ago, I did see a badly molting, pretty thin leghorn, whip some manners into my roo, who is turning out to be a peach.
You will get good egg laying from the leghorns...... which could help you wait for eggs from the dual purpose girls. You might notice that while free ranging, the different colors tend to hang together a little more, but generally raised together, stick together pretty good.
Welcome, this is a fun hobby!
Mrs. K