The purpose of this study was to investigate the effect of mash and pellet feed physical form during different rearing period on performance, uniformity and gastrointestinal track changes of laying pullets. A total of 340 pullet of Hy-line (W36) were randomly distributed between five treatments (three treatment with 6 replicates and two treatment with 8 replicates) of 10 birds each. The experimental treatments included A) the birds that fed with mash form during fourteen weeks, B) pellet feed during the first 4 weeks and mash feed for 5 th to 14 th weeks, C) pellet fed for the first 8 weeks and mash feed for the next six weeks, D) pellet feed for the first 12 weeks and mesh feed for the last two weeks, E) pellet feed for the whole fourteen weeks. Daily weight gain (DWG), feed intake (FI) and feed conversion ratio (FCR) were measured every other week. At the age of 14 weeks, one bird from each replicates was randomly selected, weighted and killed. After dissection, the relative weight and length of the digestive organs were measured. In addition, the pH of gizzard contents were measured. The results showed that the birds fed pellet diets (treatments B to E) had higher FI and DWG compared with mash form (p 0.05) during first two weeks. The average of FI in treatments that used pellet feed were higher when compared with those fed mash feed (p 0.05). Between the 4 th to 6 td weeks, the average FI in pullets that fed pelleted diet for first 4 weeks (treatment B), was higher when compared with pullets that fed with mash feed (p 0.05). No significant differences in performance parameters were observed between treatments during 8 th to 10 th weeks of experimental period. The FI increased in treatment E during 9-10 weeks of experiment (p 0.05). In 12 th weeks, treatment E had better FCR comper to A (p 0.05). Totally, C, D and E treatments had greater FI compared to treatment A during total experimental period (p 0.05). The gizzard weight in the birds fed mash diet was significantly lower than other treatments. There were no significant changes in length of digestive organs between the treatments that fed mash and pellet feed. In conclusion, pellet feeding at least for first four weeks showed improved DWG, FCR and body weight uniformity as compared with mash feed. Keywords: pellet fed, mash fed, uniformity, pullet
