They should be off chick grit - get grower or layer grit at this point (ideally with mixed sizes) and they can pick out the pieces they want.
If you know you have a variety of hard rocks/pebbles in your environment that the chickens have access to year round (which includes winter, when the ground is frozen or under snow), then buying it isn't necessary. But considering how cheap it is, it's pretty easy to provide and a bag will last forever.
If you know you have a variety of hard rocks/pebbles in your environment that the chickens have access to year round (which includes winter, when the ground is frozen or under snow), then buying it isn't necessary. But considering how cheap it is, it's pretty easy to provide and a bag will last forever.
