For an example of a similar pair of pigs, see J.J. Lally, Arts of the Han Dynasty, 1998, Catalogue, no. 10 where the author references a similarly modeled pair of pigs in the Collection of the Harvard University Art Museums also illustrated by M. Loehr and L.G. Fitzgerald Huber, Ancient Chinese Jades from the Grenville Winthrop Collection, p. 387, no. 555, where Huber cites a very similar example found in an early Eastern Han tomb at Beizhuang, Dingxian, Hebei, which was assigned on epigraphic evidence to the period 56-88 A.D., illustrated in Kaogu xuebao, 1964, no. 2, p. 148, fig. 4.
Compare also the jade pigs of this type carved in the same classic style, sometimes referred to as 'Han Eight Cuts,' illustrated by W.P. Chung in the catalouge of the 1996 Hong Kong Museum of Art exhibition, Chinese Jade Animals, pp. 68-69, nos. 36-38.