... [P]ecking is such a complex process of prehatching and posthatching development, involving so many morphological, physiological, and environmental factors, that it would be quite naive to argue whether it is "innate" or "learned" or whether or not this behavior had already been acquired in the shell... both concepts, of instinct and of learning [are] obsolete... [All viewpoints] on the concept of innate behavior amount to one thing: predeterminism or finalism, verging on vitalism.
Kuo (1967, pp. 109-110, 112)