Abstract: 【Objective】The hatchability of Miniature Layers and hybrids was investigated and the differences of embryonic, mortality, the ratio of egg water loss, and hatchability at different altitudes were analyzed.【Method】Eggs from four groups of chickens, Miniature Layers (M), Miniature Layers fed in Tibet (MT), Tibetan × Miniature Layers (TM), and Tibetan (T), were incubated at 2 900 m an altitude of 2 900 m (Linzhi, Tibet) and an altitude of 3650 m (Lhasa, Tibet), and their embryonic mortality, water loss and hatchability were measured. 【Result】The hatchability of M and TM at an altitude of 2 900 m was 49.44% and 74.69%, respectively. Although it was fed in high altitude environment, MT did not decrease in water loss, and increased a little in hatchability, as compared with M. At 3 650 m an altitude of 3 650 m the embryonic mortalities of all groups increased, and the hatchabilities and ratios of hatch weight to egg weight decreased; and the hatchability of T was 30.70% while that of M was about 10%. 【Conclusion】The results indicated that the water loss was high, and the hatchability of Miniature Layer was low at high altitude, but the heterosis of hatchability of crosbred of T×M was significant.

Key words: Miniature Laying chicken, high altitude, embryonic mortality, hatchability, losing water