Mycotoxins — toxic compounds produced by moulds in grain — contaminate poultry feed and cause significant welfare harm including immune suppression and organ damage.
Mycotoxin contamination of poultry feed represents a hidden welfare threat because subclinical exposure causes immune suppression and organ damage without obvious clinical signs. Affected birds are more vulnerable to respiratory and other diseases; their immune systems cannot mount adequate responses to vaccination or natural infection. The chronic nature of mycotoxin exposure means that welfare harm accumulates over the production period without reaching the threshold of visible clinical disease. Good feed hygiene, appropriate storage, and mycotoxin monitoring prevent this form of welfare harm at low cost relative to the disease costs of immune-compromised flocks.