Most chicken farmers nowadays make sure that feeding and watering chickens are done in the most efficient manner to maximize production. Even if the chickens are considered unfit for human consumption, they could become chicken by-product meal. According to the Association of American Feed Control Officials, chicken by-product meal is made of rendered parts of the carcass of the slaughtered chicken. This includes feet, undeveloped eggs, entrails, and necks.
Parts that should not be used as ingredients
There are strict legal definitions of what can be part of a by-product meal. For example, hair, feathers, manure, and intestinal content, and anything that is not specifically part of the carcass can’t be used as an ingredient. A small quantity of feather is accepted due to processing practices.
Chicken meal vs chicken by-product meal
The only difference between these two products is that chicken by-product meal includes head, feet, and intestines. Some people could believe that by-product meal has an inferior percentage of protein because of its ingredients, but scientific research proved there is no nutritionally important difference between these two categories.
It was believed that the higher quantity of ash contained in chicken by-product meal negatively influenced the digestion of proteins. However, scientific work has proved that a bigger content of ash does not reduce protein digestibility.
Moreover, several studies have determined the digestibility and the quality of proteins and amino acids in rendered products. The results of these studies stated that there are no differences in the quality of the proteins.
From a nutritional point of view, there is not a significant difference between a chicken meal and chicken by-product meal. However, this doesn’t mean that all of these products are of equal quality. Various differences may be caused by different processing or by the characteristics of each ingredient.
How chicken waste is processed
Transforming chickens’ intestines, bones, and flesh into chicken by-product meal takes a few steps. The ingredients are collected in large metal barrels where they are stabilized through fermentation. Another method is to use acid or basic treatments. In neighborhoods where odors are not tolerated, manufacturers use the method of freeze-drying to stabilize the chicken carcasses.
This first step of the process stops bacterial and viral expansion and lowers the pH. In order to preserve the ingredients, manufacturers use mineral acids or sodium oxide. The old method of processing offals is wet rendering (cooking under steam pressure). This method is currently replaced by dry rendering so meals of higher quality can be obtained.
What you should know about dry rendering
The process used to obtain chicken by-product meal is known as „rendering”. During this process, raw parts of the chicken are meticulously prepared at very high temperatures (approximately 140°C or 284°F) to get the water and fat out of the bone and remaining tissues. In general, the evacuated fat is sold as poultry fat.
The remaining blend is dried and the process continues by grounding it until it becomes a fine powder. The result can be sold as chicken meal or chicken by-product meal if heads, intestines, and feet were put into the mixture.
The influence of the temperature
The way the rendering is completed has a great influence on the final product quality. If the temperature is too high or the cooking time is too long, the digestibility of the protein’s amino acids will be remarkably reduced.
The protein’s quality present in chicken by-product meal
The quality of the chicken by-product meal is also influenced by the part of the chicken incorporated. A team of scientists analyzed the quality of different parts of rendered chickens. They used Protein Efficiency Ratio (PER) to determine the protein quality.
The research showed that rendered chicken feet had the smallest PER of 0.87, while bones had a PER of 1.22, and heads contain a higher PER of 2.5. Internal organs such as liver, heart, and gizzard had an indicator of PER equal to 3.04. An entire bird without feathers has a PER of 3.43.
Despite big differences in the protein quality present in bones, intestines, and feet, chicken by-product meal has the same nutritional values as chicken meal. The reason is that chicken by-product meal contains a small amount of chicken parts having a small PER.
The most important factor
The last factor influencing the quality of a rendered chicken product is how fresh and how high in terms of quality the meat of the birds is. The time between the chickens’ death and the start of the rendering process should be as short as possible.
Chickens good enough for human consumption and processed right after slaughter will be used to obtain the best quality rendered products. Still, producers are using birds that were not considered fit for human consumption or not freshly killed birds, obtaining a final product with low quality.
A trustworthy food company will check its chickens and only accept the ingredients that are good quality. It needs to analyze the level of ash in order to determine if there is too much bone in the final product.
A big quantity of ash might affect the levels of calcium and phosphorus required for a healthy diet. Furthermore, these companies will try to obtain a specific level of protein for their product. This means that they will use much more chicken meat than bones.
The usefulness of some ingredients
The idea of chicken feet might seem gross to us but they are just bones with a small quantity of muscle. In some parts of the earth, people think of chicken feet as a delicacy. Veterinarians recommend a certain amount of bones in a dog’s diet. Including bones in your pet’s food regime will help it maintain a proper level of calcium or phosphorus.
Chicken eggs, entrails, and various organs have amazing nutritive potential. Keep in mind that for intestines to be processed they must be cleaned so they don’t contain harmful bacteria. Even liver, kidney, and heart are part of the chicken by-product. These are very nutritious and your pets will consider them a treat.
Always check the label
Chicken by-product meal can easily be identified on the food label. You might think it will be easy to draw your own conclusions about the quality of the product. However, useful information is not included in the product’s label. There is no way to find out how attentively the rendering process was controlled or how fresh the birds were. Not even the quantity of different body parts contained is mentioned on the label.
There is no way of knowing whether it contains 90% meat or if it is a mixture of flesh, bones, and feet. This is why there is great variability in quality for this type of product. Often, when the label specifies „chicken by-product” it might include very nutritious ingredients or it can be a blend of useless and cheap ingredients.
Changing the name
Some manufacturers observed that pet owners avoid buying merchandise labeled „by-product”. They are currently trying to convince the Association of American Feed Control Officials (AAFCO) to remove the word „by”. However, the new name might be misleading to clients.
Boneless chicken by-product meal is also available
Some of the foods marketed as top dog foods claim to contain ingredients such as boneless chicken. It only makes you wonder about the content of this product. Boneless isn’t necessarily better. If a producer uses the word „chicken” it can mean any type of meat (not necessarily thigh or breast meat). It could be 80% feet muscle or even skin.
Also, the term „fresh” doesn’t guarantee better merchandise. It simply means that the meat came directly to the factory, without being frozen. There, it was made into a dry form so it could be packaged. Buying fresh chicken by-product meal doesn’t assure it to have more nutrients or be more healthy.
Impacting the environment
As you may assume, buying chicken by-product meals is good for the environment. As discussed earlier, the parts of the chicken that humans don’t eat have great nutritional values for our dogs. If we didn’t transform these scraps into pet food, then they would remain unutilized and would go straight into the trash bin.
If all people decide to give their pets only food made of breast and thighs, the effect on the environment would be extremely negative. Tons of food would go to waste and the number of chicken farms would have to increase overnight. Also, the price paid at the local supermarket for chicken products would be higher.