In this paper, vocalizations of laying hens (Hyline Brown) were focused. An experiment was designed to obtain acoustic features of laying hens with different ages: 35days-old, 95days-old and 125days-old. Vocalizations were recorded by the microphone MPA201. Analysis was done by some analytical software in order to gain time-domain features and frequency-domain properties of laying hens’ sound. The duration time, pitch frequency, formant track and spectrums of vocalizations were all included. Results showed that some characteristics of vocalizations of laying hens with different ages were dissimilar when under given state. It was proved that the vocalization of laying hens could be recognized and identified.