Once that happened, they wanted nothing more than to be with the rest of the chickens. I would let everyone out for a while in the evening and the new chicks would end up in the hen house at dark. I spent a few nights grabbing chicks from the roosts and putting them in their new home. I couldn't do this anymore, so I put everyone together and started trying to figure out how to feed them so they get the proper nutrition.
Presumably - feeding starter to everyone wouldn't be bad, except the laying hens might need more calcium for their eggshells. Feeding layer rations might be fine too, but the young birds might be stunted. I did some research and had a hard time finding solutions to this problem. What I found out about feeding chickens was informative. This is in no way definitive, but it sounds good:
When to switch from starter/grower feed to layer feed:
Some people switch around 20 weeks of age. They think it's good to get a head start on the extra calcium, so, when they do begin laying, they're ready for it. Other people did thinks differently. Some didn't think there was an exact time to switch. I read a post where someone recommended that when they start laying, to finish off the bag of starter/grower before switching to layer feed.
People do have strong opinions about feeding layer feed to chicks that aren't laying yet. Young chicks don't need the extra calcium that is found in layer feed. Apparently it has some negative health consequences - affects bone development. Makes sense. The one recommendation that I saw the most was to feed everyone starter feed and put out crushed oyster shell for the layers who need the extra calcium. That seems like the best idea to me. So I'm off to the feed store to get starter/grower feed and some crushed oyster shells.