I give cherrystone grit size #3 to my LF and #2 to my bantams. If you are feeding anything other than cracked grains (or pellets etc.) then you need to make sure they are free ranging with access to grit or give them grit. Otherwise they cannot digest properly.
Come winter if you get a real winter they'll need grit supplement. It's a simple as going to a crushed stone yard and getting a small pail full of #4 stone. Passes through 1/4 inch screen to retain on #4 screen. Or rake some up from the road shoulder
If you don't provide grit they'll consume far more feed as it's their primary digestive system and will pass through much undigested feed as waste. Birds eat small stone (angular is better) to grind food in crop before it goes to stomach. To not have it is like us eating without teeth.
My chickens free range everyday for about an hour or two depending...This is my first year raising chickens and so far they're doing okay. I feed them corn scratch but when they are all 16 weeks+ I will feed them layer feed. I have chickens of all ages and not needing anymore! Already have 11! lol