In this paper, the laying rate of 72-week-old 4 duck breeds, designated Jinyun-, Shaoxing-, Gaoyou- and Khaki-Campbell ducks, is fitted by polynomial model, which gives �values of 0.975, 0.884, 0.973 and 0.995 for the 4 breeds, respectively. This result may provide the scientific foundation for selecting, raising, feeding ducks and the studying of the rule of their producing eggs.
