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Anticoagulant Rodenticide Toxicity

Brodifacoum Toxicity, Dicumarol Toxicity, Warfarin Toxicity


Anticoagulant rodenticides are a frequently used rodenticide that are categorized as first-generation or second-generation. First-generation anticoagulents include warfarin and indanediones such as chlorophacinone and diphacinone. Due to an increase in rodent resistance to first-generation chemical compounds, second-generation compounds were developed that were designed to kill rodents quicker and after one feeding, as opposed to the first-generation compounds which usually require multiple feedings to induce poisoning, with concentrations ranging from 0.025 to 0.005%. Second-generation anticoagulents include brodifacoum, bromadiolone, difenacoum, and difethialone. Today, second-generation anticoagulents are more commonly used than first-generation compounds. Anticoagulents are often produced as wax blocks, tracking powders, and pellets.

The problem with rodenticides is that they have the same effect when eaten by any animal, including chickens. Upon ingestion, anticoagulants inhibit epoxide reductase which reduces the ability for the chicken to regenerate vitamin K. As the remaining vitamin K depletes, it will lead to inhibition of coagulation synthesis. Depending on the amount of poison ingested, there will be a delayed onset of clinical signs of toxicity. Clinical signs will generally take a couple days to develop after exposure to a toxic amount of anticoagulants and are often non-specific such as loss of appetite, weakness, and depression.

Clinical Signs

Loss of appetite
Hemorrhaging of feather follicles
Pale colored comb and wattle
Excessive bleeding


  • History
  • Clinical signs
  • Physical exam
  • Anticoag/Rodenticide screen test


Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
Vitamin K10.2-2.2mg/kg given IM or subcutaneously every 4 to 8 hours until stabilized.
Once stabilized, it is administered usually once daily for at least 2 weeks or longer, depending on the severity.
Blood transfusionIn severe cases


  • Do not keep rodenticides anywhere near where chickens could possibly access them
  • Do no use rodenticides, use a different method of rodent control.

Scientific References

Risk Factors

  • Leaving rodenticides in the vicinity of where chickens are kept and can easily access them.