Congrats on your new family members.
Chick Starter is still good for another month or so.
After that you need to feed them a good hen feed, like a laying crumble. Mix 1/8 scratch into the crumble. Also, you can mix the chick starter in the a good hen feed.
You also need to give them some fruit and veggie treats they may like. Some fruits are good in season. Apples are great. My girls love melon seeds, water melon rind, etc. They won't eat what they don't like. Nothing tangy or two spicy. Mine also like fresh spinach.
In addition, later you can introduce some sunflower seeds as a treat. When my girls are laying I give them some canned dog food once a month or so. Extra protein.
Also, when they start laying it is VERY important that you have a separate bowl of oyster shell available. This is really important so they get enough calcium. Also,don't forget they need plenty of fresh water every day.
Watch for predators from the sky. Do you have hawks? I'm guessing you lock them up tight at night.
Bottom line, when they get to about six months, introduce a variety of foods, commercial and otherwise.
I also suggest you buy Gail Damerow's "The Chicken Health Handbook." This book is the bible of raising chickens. It is available online.
Good luck,
Geri