Performance and Eggshell Quality

During the experiment, eggs were collected at 16:00 p.m. every day. The number of eggs produced per day on a repeating basis (including eggs with a soft shell, broken shell, and different shape, which were being treated as unqualified eggs) were recorded to calculate egg loss (the number of unqualified eggs per replication divided by the total number of eggs per replication) and egg production (the total number of eggs per replication divided by the number of experimental days [56] and divided by the number of hens per replication [15]).

Per replication, 2 eggs were collected randomly at the end of the 8th wk. The eggshell strength was assessed by using a digital egg tester (DET-6000, Nabel Co., Ltd., Kyoto, Japan), and eggshell thickness was measured using an eggshell thickness gauge (ESTG-1, Orka Food Technology Ltd., Ramat Hasharon, Israel) at 3 points (sharp end, blunt end, and the equator) after removing the eggshell membrane and estimated by the average of 3 points from each egg (Li et al., 2018a).