Toxicity causes immunosuppression and ultimately poor performance.

Toxins are introduced in the body through consumption of defective feed, contaminated water, chemical medication and inhalation of poisonous gases or fumes. This may also include microbial pathogens, fungal metabolites and allergens absorbed through lungs or skin. Poultry is continuously exposed to these toxins making birds more prone to diseases. There could be acute or chronic toxicity due to cumulative accumulation of toxins. In the natural circumstances, the toxins are flushed out of the body mainly by liver, kidneys and blood. It is only when the toxin levels reach beyond the capacity of filtration by the body, toxins start accumulating and toxicity symptoms develop.