ABSTRACT Background: Because maintenance of the immune system is thought to be resource-limited, trade-offs between immune function, body condition, and reproductive allocation are expected. Questions: Do females confronted with the simultaneous challenges of immune stimulation and supernormal egg production face a trade-off in terms of self-maintenance (body mass and blood parameters) and/or egg quality? Organism: Red-legged partridge, Alectoris rufa, a precocial bird species with a huge investment in eggs. Methods: We challenged the immune systems of females, before egg laying, with a novel antigen (Newcastle Disease virus vaccine, NDV). We also removed eggs as they were laid, so as to induce supernormal egg production. Conclusion: Compared with the other eggs, the last-laid eggs of hens with supernormal production were smaller, contained less yolk, had a lighter shell, and contained albumen with less lysozyme. However, the immune challenge had no effect on female condition or egg quality. Thus we found no evidence of a trade-off between immune function, body condition, and reproductive allocation
