Scratch and Peck Feeds - Cluckin' Good Layer Grit Supplement for Chickens and Ducks - 7-lbs NECESSARY FOR DIGESTION - Chickens do not have teeth. Grit is necessary for the healthy development of a chicken's gizzard. APPROPRIATE FOR LAYING POULTRY AGES 20 WEEKS AND OLDER APPROPRIATE FOR BROILERS 4 WEEKS AND OLDER AVAILABLE IN DIFFERENT SIZES, DEPENDING ON SIZE AND AGE OF THE BIRD