poultryprofessor
Chirping
Like I said above, I feed all flock. I never feed layer pellets as I dont always have layers. Between 18 birds someone is always molting, broody, or just not laying.
My bad - definitely missed that.
In that case, pellet size is all you need to worry about. I use Nutrina Nature wise All Flock pellets for my adult bantams. They're smaller than a lot of 7 or 8 week old large fowl.
Another question I would have is about your feeder set up. What kind of a feeder are you using and how high is it relative to your birds? Are they scratching feed out? Flinging it out? What is making the mess? This could be something we can help with.