I don't think it really matters. I think Purina is trying to say that the blocks are not meant for caged birds. We use them as a supplement in the barn in the dead of winter when there is no pasture available for our flock.
According to the label I have in front of me...
Purina Flock Block - Whole Grain Enrichment Supplement
-For free-ranging poultry and game birds
-Encourages natural pecking instincts to help reduce cannibalism
-Contains oyster shell and grit
Guaranteed Analysis:
Crude Protein not less than 8.0 %
Lysine not less than .30%
Methionine not less than .25%
Crude Fat not less than 2.5 %
Crude Fiber not more than 4.0 %
Calcium (Ca) not less than 2.3 %
Calcium (Ca) not more than 2.7 %
Phosphorus (P) not less than .65%
Salt (Nacl) not less than .70%
Salt (Nacl) not more than 1.2 %
Sodium (Na) not more than .35%
Ingredients:
Cracked corn, Whole wheat, Whole milo, Whole barley, Whole sunflower seed, Molasses, Oyster shell, Calcium Lignin Sulfonate, Dicalcium Phosphate, Granite grit, Salt, Propionic Acid (a preservative), Choline Chloride, DL-Methionine, L-Lysine, Pyridoxine Hydrochloride, Thiamine, Biotin, Vitamin A Acetate, Nicotinic acid, Riboflavin, DL-Alpha tocopheryl acetate, Cholecalciferol, Menadione dimethylprimidinol bisulfite (source of Vit K), Folic acid, Cyanocobalamin, Manganous oxide, Zinc oxide, Copper sulfate, Calcium iodate, Sodium selenite.
Ruminant Meat and Bone Meal Free
How to Feed:
Flock Block supplement is designed to supplement the diet of poultry 18 weeks and older. This is not intended to be the sole ration. Place blocks on the ground, free-ranging poultry and game birds will regulate their consumption according to the availability of natural diet. A feeding program is only as effective as the management practices followed and should only be used in combination with good conservation practices.
Caution:
Use only as directed. Store in a dry area away from rodents and insects. Do not feed moldy or insect-infested feed to animals as it may cause illness or death.