Heaton M B
J Comp Physiol Psychol. 1976 Jan;90(1):53-6. doi: 10.1037/h0077252.
The onset of visual system function in the wild red jungle fowl embryo was measured by the pupillary reflex technique and compared with its domesticated descendant, the domestic chick. The first neurally mediated pupillary reflex in the jungle fowl embryos was found at Day 15 of incubation after 77% of incubation was completed. This point did not differ significantly from the onset of this reflex in the domestic chick embryo (after approximately 83% of incubation). Thus, it was concluded that the relatively late onset of overt visual system function in the chick, as compared with several other precocial avian species, was not a result of its history of intense domestication but rather was most likely a normal characteristic of this and other closely related species.
通过瞳孔反射技术测量野生红原鸡胚胎视觉系统功能的起始时间，并与其驯化后代家鸡进行比较。在孵化77%完成后的第15天，发现原鸡胚胎出现了首次神经介导的瞳孔反射。这一点与家鸡胚胎中该反射的起始时间（孵化约83%后）没有显著差异。因此，得出的结论是，与其他几种早成鸟类相比，家鸡明显的视觉系统功能起始时间较晚，这不是其长期驯化历史的结果，而很可能是该物种及其他密切相关物种的正常特征。
