The study evaluated the effects of
Citrullus lanatus
essential oils inclusion in diet on egg production, egg quality, and physiological parameters in layer hens. A total of 72 White Leghorn point-of-lay hens at 18 wk were used for the study. The hens were randomly allocated to following 3 dietary treatments: 1) commercial layer diet (control), 2) commercial diet + 1 g
C. lanatus
essential oil/kg feed (
1gCL
), and 3) commercial diet + 2 g
C. lanatus
essential oil/kg feed (
2gCL
). Each treatment was replicated 8 times arranged in completely randomized design. From the results, an increase in total weight gain, average daily feed intake, and average daily gain was observed with inclusion of the
C. lanatus
essential oil. In addition, the inclusion of
C. lanatus
in diet improved the egg mass and feed conversion ratio (
FCR
). Hens fed
C. lanatus
–containing diets had higher egg mass (1gCL, 53.35 g ± 0.71; 2gCL, 53.99 ± 0.71 g) compared with the control (52.90 ± 0.71). The
C. lanatus
containing diets also had lower FCR than the control (1gCL [2.18 ± 0.22] and 2gCL [2.16 ± 0.22] vs. control [2.20 ± 0.71]). With regards to egg quality parameters, inclusion of
C. lanatus
oil appeared to reduce shell weight and shell ratio, while increasing albumen height and Haugh unit. Diets containing
C. lanatus
had significantly higher amounts of stearic acid, and linoleic acid was highest (
P
< 0.05) in the 2gCL fed hens. Birds fed the 2gCL diet (15.29 ± 0.60) had the highest total polyunsaturated fatty acids, total n-6 fatty acids (14.81 ± 0.59) and also had the highest n-6/n-3 ratio. An increase hematological values was observed with inclusion of
C. lanatus
essential oils in diets. Moreover, tibia bone parameters were also significantly improved with inclusion of
C. lanatus
essential oils in diets. It can be concluded that
C. lanatus
essential oil positively affected egg production, and quality and health of layer hens can be used successfully as a natural feed additive.