Almost all chick starter products have grit in it. Also gryeyes said it best Construction sand is the best you can also offer them clumps of dirt from the yard they will find grit in it. I suggest this anyhow if you feed medicated starter and don't allow them access to dirt. the dirt helps them build an immunity to cocci. If you medicate them without the exposal to dirt your really treating nothing (assuming your very clean in keeping there brooder area tidy) hope this might help.