8Von Borell E, Hurnik J F. Stereotypic behavior, adrenocortical function, and open field behavior of individually confined gestating sows [J]. Physiol Behav, 1991, 49(4) : 709-713.
9Morgan C A, Lawrence A B, Hunter E A, et al. Effect of meal frequency and rate of nutrient supply on the post-feeding behaviour of the pig [J]. Appl Anim Behav Sci, 1995, 61: 565-573.
10Tawence A B, Terlouw E M C. Review of behavioral factors involved in the development and continued performance of stereotypic behaviors in pigs [J]. J Anim Sci, 1993, 71: 2815-2825.
