Chickens enjoy nibbling on grasses and weeds in addition to their regular feed. Free-range chickens will snack on a wide variety of plants, and even cooped chickens have been known to peck at any plant that they can reach. However, chickens do not know that the plant they're eating for lunch is an undesirable weed that you just sprayed with herbicide.
Herbicides are plant killers that come in a variety of forms and chemical compounds. Usually, an herbicide is used to eliminate weeds from the lawn or from in between cracks in the sidewalk. Occasionally, herbicides are used to kill weeds in areas that are difficult to keep mowed like along the edge of a shed or other outbuildings. Herbicides are also used inside garden areas to kill weeds that take nutrients away from the desired flowers or vegetables.
The chemical compounds found in common herbicides include chlorophenoxy and nitrophenolic compounds and glyphosates. Chlorophenoxy compounds are acids and salts used primarily as plant growth regulators, and the compounds may make undesired plants taste better to grazing and foraging animals, increasing their consumption of the treated plants. Nitrophenolic compounds are used worldwide as herbicides, fungicides, nematocides and ovicides. Glyphosates are the active ingredients in the popular weed-killing product Roundup.
If ingested, inhaled or absorbed through the skin, each one of these chemicals can produce extreme physical reactions in both humans and animals. Chlorophenoxy is essentially nontoxic, but when applied in high doses, induces vomiting, confusion, unusual aggressive behavior, anorexia, weight loss and muscular weakness. Pentachlorophenol causes eyes, nose and throat irritations, labored breathing, tremors and muscle spasms. Nitrophenolic compounds are readily absorbed through the skin and lungs and are highly toxic to all animals causing sweating, thirst, fever, confusion, restlessness and a yellow staining of the skin from prolonged exposure. Glyphosates are mildly toxic causing nausea, vomiting and staggering in animals exposed to freshly treated foliage.
Chickens will peck at any foliage in reach just to test its appeal as food. Penned chickens are also at risk of rain and irrigation water runoff bringing herbicide compounds inside their housing. Herbicides can cause serious physical reactions in chickens. Even less toxic herbicide compounds that don't physically harm your chickens will be transferred to the eggs you eat. To ensure the health of your flock, keep weeds at bay with mowing and hand pulling instead of toxic chemicals.