Normal growth and development pattern of selected internal organs of domestic duck (Anas platyrhynchos) during pre-hatch period was studied in this project. Tongue, esophagus, proventiculus, gizzard, small and large intestines, liver, kidneys, trachea, lungs, brain, eye balls and heart were studied for morphometric measurement. A total of 120 healthy fertile domestic duck eggs were equally divided into 24 groups (n=5). Eggs were weighed, labeled and incubated. All groups were examined during incubation; collection of embryos was started from day five on daily basis but recordable observations were obtained from day 10 of incubation. Means and standard errors of mass and length of selected internal organs were calculated for each age group till hatching. Growth rate of duck was measured by applying Janoscheck growth curve to age group means. Results revealed a sigmoid to exponential growth curves for organs’ maturity. Growth pattern grouped organs into: eyes, brain and trachea with early rapid growth; liver and some digestive organs having intermediate growth; while heart, lungs, kidneys and esophagus attained maximum maturity towards the end of incubation. It is conceivable from the data that most of the parameters under study show complex allometry, i.e., the ratio of relative growth rates between organ and whole body changes several times however, these transitions are gradual.

Key words: Development, Ducks, Growth, Janoscheck growth curve, Morphometry