SUMMARY

Egg shell breakage is and remains a source of economic loss to the egg producer. In general, about 3% of the eggs laid by hens housed in battery cages or in free-run systems have cracked shells. This number increases about another 1% for hens kept in enriched cages or housed free-range and a further 1 to 2% for those in aviaries. The range of cracked shells reported was from 2 to 12%, but there were few published reports for most production systems. The occurrence of dirty-shelled eggs is about 2 to 3% higher than the incidence of eggs with cracked shells. Shell breakage is also influenced by manufacturer of enrich cage systems. The highest impact eggs receive as they move from the hen to the retail store is in the laying house; overall, eggs receive impacts that average about 13 G. The material used to make egg cartons (paper pulp or plastic foam), the cases in which the cartons are shipped (cardboard or wire), and the location of a carton within the shipping case (top, middle or bottom) affect the occurrence of shell breakage when eggs are transported. Even apparently weak impacts to egg shells may cause microcracks to develop and if the impacts are stronger visible cracks become apparent or they may rupture the mammillary membranes which will allow the egg’s content to escape.

概括

蛋壳破损是并且仍然是鸡蛋生产者的经济损失来源。一般来说，饲养在电池笼或自由运行系统中的母鸡产下的鸡蛋中，约有 3% 的鸡蛋有破裂的蛋壳。对于饲养在丰富的笼子里或自由放养的母鸡，这个数字又增加了大约 1%，而对于那些在鸟舍里的母鸡，这个数字又增加了 1% 到 2%。报告的破裂外壳的范围从 2% 到 12%，但大多数生产系统的已发表报告很少。脏壳鸡蛋的发生率比破壳鸡蛋的发生率高约2%～3%。外壳破损也受到浓缩笼系统制造商的影响。鸡蛋从母鸡运到零售店时受到的影响最大的是产蛋舍；总体而言，鸡蛋受到的影响平均约为 13 G。用于制作鸡蛋纸盒的材料（纸浆或泡沫塑料）、纸盒装运的箱子（纸板或金属丝）以及纸箱在装运箱内的位置（顶部、中部或底部）都会影响鸡蛋的发生。鸡蛋运输时蛋壳破损。即使对蛋壳的明显微弱的撞击也可能导致微裂纹的产生，如果撞击更强烈，可见的裂纹就会变得明显，或者它们可能会使乳头膜破裂，从而使鸡蛋的内容物逸出。