Antibiotics are included in minute levels in chicken (Gallus gallus, Linnaeus, 1758) rations to promote productivity and physiological well-being. Studies have found that persistent use of antibiotics in feed to increase chicken performance, is linked to the appearance of resistant bacteria and build-up of residues in animal products. These anomalies have resulted in prohibition of antibiotics in animal feed in many countries of the European Union and interest in the use of yeast (Saccharomyces cerevisiae) as a growth enhancement agent in chicken rations. Yeast is highly proteineous (44%) but modest in other essential nutrients. Yeast supplementation is known to enhance gut health and feed efficiency in chickens. This paper pools available data from studies that investigated the impact of yeast on health status, egg production and egg quality in laying chickens so as to identify knowledge gaps for future research.