The palisaded enclosures by Silbury have evidence of pig offerings in the post holes, quote from Whittles book on Silbury and Palisade enclosures, (Sacred Mounds, Holy Rings)

palisade posts indicate the immediacy of bone treatment. Cattle may have been valued for ritual and slaughter (greater fragmentation of cattle bones) no evidence for marrow extraction.
Ritual and deposition; animal bone was placed around posts in the process of backfilling the ditches and constructing the palisades. Slaughter, sacrifice, feasting and deposition were closely related...In late neolithic long established tradition of feasting, the enclosures were overlooked by the ancestors in WKLB, most bone concealed but some left on top as a visual reminder for later gatherings...pigs may have had symbolic meaning in their own right. Emphasis on right side may be connected with a sense of propitiousness...comparing them to tribes in
Papua New Guinea - a largely vegetarian society, their pigs were bound
up with warfare and peace making, spirits and ritual, reared from a young age by women. When pig numbers reached a peak a kaiko was held. Pigs were slaughtered but not all eaten they were sacrificed, the ceremony was designed to bring peace with neighbouring tribes..

There are others on this forum that believe pigsticking went on in Avebury henge