Hughes B O, Gilbert A B, Brown M F
Br Poult Sci. 1986 Jun;27(2):325-37. doi: 10.1080/00071668608416885.
Concern regarding the proportion of brown eggs being laid with abnormal egg shells led to an investigation of the relationship between disturbance or stress and egg shell appearance and quality. The abnormalities fell into two main classes: misshapen or bulging eggs and eggs coated with a superficial layer of amorphous calcium, variously termed dusted, white banded, chalky or pink eggs. Translocation of hens from pens to cages resulted in a decrease in egg production and an increase in the proportion of abnormal eggs over the succeeding 18 d. Disturbance to flocks on deep litter resulted in an increase in the proportion of eggs laid with abnormal shells on the following day, not only in the flocks directly affected but also in an adjacent flock. Exclusion from their nests of birds accustomed to laying in nest boxes resulted in disturbed prelaying behaviour, retention of eggs in the shell gland and an increased proportion of coated eggs. Administration of 0.1, 0.25 or 1.0 mg of adrenaline subcutaneously resulted in the retention of eggs currently in the hens' shell glands and in an increased proportion of eggs with abnormal egg shells being laid during the following 10 d. A dose response effect was apparent. There was evidence that the nature of the particular abnormality produced was dependent on the stage of egg formation at which the disturbance was imposed and, if retention followed, upon the length of time the egg was retained. Disturbances when eggs were only lightly calcified tended to result in misshapen eggs, while those occurring when oviposition was imminent tended to result in coated eggs. Dusted or pink eggs followed moderate retention whereas white banded eggs were seen after prolonged retention. These observations may provide a basis for a non-invasive method of assessing stress in laying hens as well as helping to account for hitherto inexplicable occurrences of declining egg shell quality.
对产下异常蛋壳的褐壳蛋比例的担忧引发了一项关于干扰或应激与蛋壳外观及质量之间关系的调查。这些异常主要分为两类：畸形或鼓起的蛋以及覆盖有一层无定形钙表层的蛋，这些蛋有不同的称呼，如沾灰蛋、白带蛋、垩白蛋或粉蛋。将母鸡从鸡舍转移到笼子里会导致产蛋量下降，并且在接下来的18天里异常蛋的比例增加。对厚垫料饲养的鸡群造成干扰会导致次日产下异常蛋壳蛋的比例增加，不仅在直接受影响的鸡群中如此，相邻鸡群也是如此。不让习惯在产蛋箱中产蛋的母鸡进入产蛋箱会导致产蛋前行为受到干扰、蛋滞留在壳腺中以及有涂层蛋的比例增加。皮下注射0.1、0.25或1.0毫克肾上腺素会导致母鸡壳腺中当前的蛋滞留，并在接下来的10天里产下异常蛋壳蛋的比例增加。存在剂量反应效应。有证据表明，所产生的特定异常的性质取决于施加干扰时蛋形成的阶段，如果随后出现滞留，则取决于蛋滞留的时间长度。当蛋仅轻微钙化时受到干扰往往会导致畸形蛋，而在即将产卵时发生的干扰往往会导致有涂层的蛋。沾灰或粉色蛋是在适度滞留后出现的，而白带蛋是在长时间滞留后出现的。这些观察结果可能为一种评估产蛋母鸡应激的非侵入性方法提供基础，也有助于解释迄今为止蛋壳质量下降的一些无法解释的现象。
