Humans take daily vitamin supplements. Just like you, your backyard chickens may need vitamin and mineral feed supplements too!
Common feed supplements include calcium, grit, phosphorus, and salt, not including some vitamins.
The following is a list of a few chicken feed supplements that are readily available to small-scale poultry farmers and backyard chicken hobbyists.
Your layer hens need calcium to form strong, sturdy eggshells. Hens who don’t get enough calcium lay thin-shelled eggs, or eggs with no shell at all! The amount of calcium a hen needs varies with her age, diet, health, breed, and size.
Older hens need more calcium than their younger counterparts, and hens in hot weather need extra calcium concentrations in their feed since they are eating less due to the heat.
Since eggshells consist mostly of calcium carbonate, oyster shells and ground up limestone are good sources of supplementary calcium. Make sure you are not purchasing dolomite limestone, since this is harmful to egg production!
Since chickens don’t have any teeth, this important supplement is needed for proper digestion. Grit is usually sold as small pebbles or large grains of sand. These hard objects are eaten by the chickens and lodged in their gizzard. When grains, grass, and other fibrous/hard vegetation are eaten, it passes through the rocks in the gizzard where it is ground up between the stone (much like teeth). Grit should always be available, even if you’re not feeding the flock heavily with grains and vegetables. Free-ranged chickens shouldn’t need this supplement.
This vitamin is related to the assimilation of calcium and phosphorus and is needed for proper egg production. Deficiencies cause weak, thin eggshells. Vitamin D is found in cod liver oil and plenty of sunlight. Although this is a crucial vitamin, you shouldn’t need to feed extra amounts unless your chickens aren’t getting enough via sunlight or their feed.
This is one of the B vitamins and is often deficient in normal poultry feeds. If you are a breeder, deficiency of this vitamin causes embryo death during the early stages of incubation. This important vitamin is found in dairy products, yeast, liver, and plenty of leafy green vegetables.
Needed for proper health and protection from diseases, vitamin E is found in fresh greens, wheat germ oil, and whole grains (such as oats, corn, wheat, barley, etc.)
Additional offline book resources:
1. Feeding Poultry: The Classic Guide to Poultry Nutrition for Chickens, Turkeys, Ducks, Geese, Gamebirds, and Pigeons
2. Storey’s Guide to Raising Chickens
3. University of California: Feeding Chickens