Dr. Jacquie Jacob Ph.D., University of Kentuckky
As with all animals, poultry species have specific nutritional needs. The nutrient requirements of a flock are determined by several factors:
Commercially prepared organic feeds are available for the specific type and age of bird in production. It is important to provide the right type of feed. Feeding a layer ration, which is high in calcium and lower in protein, to young birds can cause serious health issues. Or, feeding a starter/grower feed to laying hens will drastically reduce egg production.
Flocks with access to pasture may supplement their diets with greens and insects, depending on the quality of the pasture. A flock will quickly devour the greens within an enclosed area, so pasture rotation is essential to maintain forage quality.
Poultry consume feed to meet their energy requirements, assuming that the diet is adequate in essential nutrients, so their daily feed intake will depend on the energy content of the diet. A high density feed has a high energy level. Since the flock will consume less feed, the nutrients must be more concentrated in the amount of feed they will consume in a day. Similarly, a low density diet has a low energy level, and the flock will consume more of the feed daily. The required levels of the different nutrients will depend on the energy level of the diet.
Energy is not a nutrient, but rather a property of energy-yielding nutrients such as carbohydrates or fats. Not all the energy in a feed ingredient is used completely. The energy value of a feed ingredient is typically expressed as metabolizable energy (ME). The ME is the gross energy content of the feed ingredient minus the gross energy lost in the feces and urine. Stated another way, ME is calculated as the energy coming in one end and the energy going out the other end. The energy levels are expressed as kilocalories of ME per kilogram or pound.
Dietary protein requirements are actually requirements for the amino acids that make up the protein. There are 22 amino acids in body proteins, all of which are physiologically required. Some of the amino acids can be produced from other amino acids and are considered non-essential. Essential amino acids are those that poultry cannot produce, or cannot produce in sufficient quantities. The two main essential amino acids that impact poultry fed a corn-soybean meal diet are methionine plus cystine (referred to as the sulfur amino acids) and lysine. The other essential amino acids may become deficient when other feed ingredients are used. When using alternative feed ingredients, therefore, it may be necessary to evaluate levels of arginine, glycine, histidine, isoleucine, leucine, phenylalanine, serine, threonine, tryptophan, tyrosine, tryptophan or valine.
A National Research Council (NRC) publication on the nutrient requirements of poultry was published in 1994. Although the information is over 20 years old, it is still referred to today. However, the fast growth rates and production levels of today's poultry stocks have warranted a modification of the nutrient requirement profiles. Furthermore, the criteria used for developing nutrient requirements have changed. The NRC requirements were developed with maximum production as the main assessment criterion. Today, additional criteria have become important, including maximum health and welfare and minimal environmental impact.
Nutrient requirements for dual-purpose breeds such as Barred Plymouth Rock and Rhode Island Red have not yet been developed.
This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.