The following analysis of factors affecting the cost and profit of the first and second egg production periods before and after mandatory moulting is performed to help the majority of chicken farmers decide whether moulting should be mandatory. 1 The cost comparison of new hens and moulting hens is one of the main purposes of mandatory moulting is to make the cost of a hen forced to moult until the start of egg production, it is less than the training of a new mother The cost of the chicken. The production cost of a mature new hen can be calculated correctly. The cost of hens to new hens production includes: (1) the market price of chickens at the time of forced moulting; (2) from moulting to chickens Feed consumption and labor costs for a group of eggs reaching 5%; (3) General management fees and other expenses during moulting. The cost of breeding a medium-sized chicken to sexual maturity is generally 13 yuan; the estimated cost of producing a commodity moulting hen is 9.5 yuan. 2 Comparison of Egg Size The eggs produced during the second egg production period are larger than those of the first egg production period. Because the size of the protein is partly related to the weight of the hen, if the weight at the end of forced moulting is greater, then the egg is also expected to be larger, but such chickens also produce fewer eggs. The size of the egg during the second laying period is, of course, also positively correlated with the size of the protein during the first laying period. A practical way to compare egg sizes is to see how much the eggs in the second flock of the same flock increase. 71% of the eggs in the first egg-laying period are large or extra large, and at least 86% of the eggs in the second laying period are large or extra large. Large and extra large eggs are shipped on egg trays and are easily broken, but they are often expensive and easy to sell. 3 Comparison of Egg Quality The change in egg quality during the second egg production period is very inconsistent. Eggshell quality was better at the beginning of the second egg production period, but decreased rapidly after 6 months of egg production. Hot weather can also accelerate the decline. In most cases the eggshell quality becomes very poor after prolonged egg production, so that the eggs must be sold at a reduced price. The change in the internal quality of the egg is not as great as the change in the quality of the eggshell. The decline in the internal quality of eggs is usually not a major economic issue. 4 Comparison of Mortality The mortality rate of chickens during the first laying period was 5.6%, and the mortality rate of chickens during the second laying period was 6.1%. Therefore, when chicken farmers are considering whether to implement mandatory moulting, in addition to analyzing market factors, they should weigh the above factors and then make correct choices, which will bring better economic benefits to the chicken farm. 5 Comparison of Egg Production The monthly egg production rate during the second egg production period was lower than the corresponding egg production rate during the first egg production period. At the peak of egg production, up to 95% of the first year's egg production rate can be as low as 85% after 6 months of production. According to the hen daily production rate, the total egg production rate during the second laying period is 90% of the first laying period, but the mortality rate during the second laying period is high. Therefore, if the number of hens per person is counted, only And 85% of the first egg-laying period. 6 Chicken's body weight and material consumption The weight of the chicken after forced moulting is greater than the weight at the end of the first egg-laying period, and will continue to gain weight during the second production period. According to the nature of the chicken, it will maintain weight gain until it reaches its maximum physiological weight, which is about two years old. Medium-sized brown shell layers can increase body weight by 340 g during the second laying period. As the body weight was greater, the consumption of material was also increased. In the test, the first egg production period consumed 121 g/(d only), and the second production period consumed 136 g/(d only). Chickens eat more during the second egg-laying period than during the first egg-laying period. In addition, the lower egg production rate significantly increases the material-to-egg ratio during the second laying period.