Effects of Hen Age and Egg Weight Class on the Hatchability of Free Range Indigenous Chicken Eggs
ABSTRACT In total, 806 eggs of free-range Hassawi indigenous chickens were collected from local farm in Saudi Arabia. Eggs were weekly collected for 11 weeks. Initial egg weight (IEW) was recorded, and eggs were graded into four classes (A: 35-40 g, B: 40-45 g, C: 45-50 g, and D: 50-55 g). Eggs were stored for seven days at 75-80% relative humidity and 14-16 C, after which egg weight losses (WL0) were calculated. During incubation, eggs were weighed on days 7 (W7) and 14 (W14), and egg weight losses on days 7 (WL7) and 14 (WL14), and total loss (WL0-14) were calculated. Hatchling weight (CW) was measured. The proportion of CW relative to egg weight loss (WL) on days0, 7 and 14 days of incubation (CW:WL0; CW:WL7 and CW:WL14, respectively), and break out analyses, fertility (F),total hatchability (HC) and hatchability of fertile eggs (HF) were also calculated. IEW decreased (p<0.05) with hen age. Stored egg weight (SEW) were decreased as hen age increased (p<0.05). WL7, WL14 and WL0-14 showed significant differences (p<0.001) and increased up to first six-week of egg collection time. Hen age affected CW:WL before incubation, and on days 7 and 14 of incubation. Fertility (F) was affected (p<0.05) in unpredicted way of increasing and decreasing by hen age. Egg weight class affected SEW, W7and W14 (p<0.001). Class D eggs were the highest weight. Class C eggs had highest HC. In summary, hatching eggs of Hassawi hens were affected by hen age and egg weight in randomly increase and decrease .