and Florou-Paneri et al. (2005) that reported Haugh unit score was not affected by oregano oil supplementation in the diet. However, more research is needed to further explore the influence of peppermint leaves and its essential oils on egg quality parameters, particularly in regard to their mode of action on egg composition in laying hens of different ages. Addition of thyme or oregano leaves at 10, 20, 30 g/kg in hen diets had no significant effect on egg quality in feeding trials during the periods of 68–72 weeks of age is also reported recently(Abdel-Wareth et al., 2013).