What NOT to Feed Your Bird
Many backyard chicken owners will give their feathery friends a multitude of treats or table scraps without hesitation. Although some foods that we eat are also edible for chickens, it is important that you don’t mistakenly feed them any foods that are toxic to them but safe for humans. When considering if a food item is safe for chickens, you must consider the food item itself and the factors that may contribute to the toxicity of the food. Below is a list of toxins dangerous for all bird species, not just poultry.
Types of Toxicants and Examples of Food
Persin
Many bird species, including chickens, can become very sick if they consume anything that contains persin which is commonly found in avocados (skin, pit, fruit, leaves and bark). Symptoms of persin poisoning in chickens include difficulty breathing, increased heart rate, disordered plumage, general weakness, and apathy. If persin doses are high enough, it can lead to death in the first 12-24 hours post consumption.
Amygdalin (Cyanide)
When digested, amygdalin breaks down into hydrogen cyanide which can lead to cyanide poisoning in poultry. Common food items that contain amygdalin are any pitted fruit along with some seeds and nuts. Common examples include apricots, peaches, plums, cherries, apple seeds, elderberries and almonds. If a chicken has digested a lethal dose of amygdalin, they can die within 15-30 minutes of consumption.
Solanine
Solanine affects the nervous system and GI tract of chickens, causing loss of motor function, GI distress, respiratory distress, and in some cases death. Solanine is found in plant stems, leaves, and flowers of the nightshade family. Examples include green or spoiled potatoes and green tomatoes (note: ripe tomato fruit and ripe potatoes are safe). If you do decide to feed your chickens any of these nightshade family fruits, be sure to remove any stems or leaves from the fruit. Potato peels have higher concentrations of solanine, so peel potatoes and check for green coloration and soft spots before feeding.
Oxalates
Consuming oxalates can cause hypocalcemia (low levels of calcium in blood) and severe kidney damage. Several food items including spinach, rhubarb leaves, and starfruit contain soluble calcium oxalates. Some ornamental plants that chickens may ingest, such as shamrocks, also contain these oxalates. Clinical signs of oxalate toxicosis include weakness, increased salivation, GI distress, and tremors.
Phytohemagglutinin (PHA)
When consumed, PHA can affect the development of a young bird’s immune system and reduce immune response for adult birds. PHA can also cause damage to the pancreas, kidneys, liver, and other organs of chickens. PHA is a lectin present in raw beans, especially red and white kidney beans. If the beans are properly cooked, PHA can be destroyed and the beans made safe. Clinical signs of PHA poisoning are not well described in birds, but the negative effects of PHA on the immune system may result in higher levels of disease and death as well as reduced egg production and GI distress.
Salt
The recommended level of salt in a poultry diet is 0.2% by weight, or around 1mg per day depending on the weight of your bird. Even small increases in salt can cause salt poisoning so you should avoid giving your birds any processed foods, such as frozen foods, snack mixes, chips, ready-to-eat foods from the grocery store and canned foods. Clinical signs of salt poisoning include excess thirst, diarrhea, and weakness. If you suspect salt poisoning, remove water and feed sources and gradually replace them with fresh water over a span of a few hours. Immediate unrestricted access to fresh water may cause brain damage.
Aflatoxins
Aflatoxins are toxins that are produced by molds or myotoxins. Aflatoxins can be present on any commercial feed that is old or moldy, old or unshelled nuts, or visibly molded food. Aflatoxins are harmful for both humans and chickens to consume. Feed contaminated with aflatoxins can transmit the toxins to eggs and chicken meat, posing a food safety concern for chicken owners. To make sure all feed and any meat or eggs harvested from the chickens are not contaminated with aflatoxins, clean up spilled feed quickly and check that your feed is still fresh by checking the expiration date and visually inspecting the feed. Clinical signs associated with aflatoxicosis in chickens include loss of appetite, loss of motor control, convulsions, depression, and death.
Caffeine
Caffeinated beverages and caffeine-containing solids, including coffee grounds and tea leaves, are toxic to chickens. Chocolate contains caffeine as well as theobromine, a compound related to caffeine that affects chickens in a similar way. Dark chocolate contains higher concentrations of caffeine and theobromine. Chickens that consume caffeine display clinical signs such as restlessness, elevated heart rate, vomiting, and seizures. At high enough doses, caffeine consumption can cause death.
While not an exhaustive list, this article covers some of the most severely toxic foods to birds. In cases of confirmed or suspected exposure to a toxic food, contact your local veterinarian or one of the two animal poison control centers (https://www.petpoisonhelpline.com/ or https://www.aspca.org/pet-care/animal-poison-control).
This article was written by Ari Sallus, Joseph Gendreau, Dr. Chelsea Sykes, Dr. Maurice Pitesky and Dr. Robert Poppenga all from the UC Davis School of Veterinary Medicine.
