Chicken as a biomarker represents proteins and peptides derived from Gallus gallus domesticus (domestic chicken). These include muscle proteins (myosin, actin, myoglobin), serum proteins, and connective-tissue proteins like collagen, as well as fragments produced during digestion or food processing. Biochemically, these are animal-derived food proteins that can be presented to the immune system intact or as smaller peptide fragments. Testing immune recognition of chicken proteins has clinical relevance because common dietary proteins can elicit measurable antibody responses in some people. Peptide-level assays and dual-isotype measurement (IgA and IgG) improve resolution by distinguishing responses tied to the gut lining from broader systemic antibody signals. This helps map how chicken-related proteins fit into an individual's overall food-reactivity pattern rather than treating foods as single, uniform exposures.

Elevated IgA or IgG responses to chicken suggest greater immune recognition of poultry proteins; IgA elevations tend to point toward mucosal or gut-associated engagement, while IgG elevations indicate systemic antibody exposure. These patterns may reflect frequency of consumption, digestion-related peptide exposure, or immune priming but do not stand alone as a diagnosis. Low or absent antibody levels typically reflect limited exposure, immune tolerance, or no measurable antibody response; absence of antibodies does not rule out non-antibody–mediated reactions. Any single chicken result is most informative when interpreted alongside other Food Zoomer markers, clinical history, and symptom patterns.

Chicken is included to evaluate immune responses to a widely consumed source of dietary protein. The marker assesses IgA and IgG binding to poultry proteins and peptides, helping providers see whether chicken contributes to clustered immune activity within meat or protein domains and supporting targeted dietary planning based on broader panel patterns.