That looks pretty good size for chicks, looks fairly 'sharp' too.
http://www.jupefeeds-sa.com/documents/GraniteGrit.pdf
They won't need grit until you feed them something other than chick mash/crumble.
http://www.jupefeeds-sa.com/documents/GraniteGrit.pdf
They won't need grit until you feed them something other than chick mash/crumble.