When you have a mixed flock, you really cannot stop birds from eating the feed. Thus, one cannot intend one kind of feed for one group of birds and another kind of feed for another kind of bird. Birds just eat whatever is available and don't read labels.
For mixed age flocks, Layer isn't a good feed choice. Grower is the better choice. Everyone can eat Grower. Some feed companies also make Grower with the names All Flock or Flock Raiser which better indicates that it can be eaten by all.
The only thing that makes Layer special is the super high calcium, something not needed by adolescents, chicks, roosters, etc. Provide your hens a calcium source on the side and normally, they are the only ones who will mess with it.