 This was intended to improve the breed's characteristics, produce hybrid vigour, and prevent inbreeding in the remaining small herds.For many years the Essex pig was considered to have become extinct in 1967, although it was thought a few pure-bred individuals might survive on small farms.Later research showed that one farmer, John Croshaw, had refused to amalgamate his herd of Essex pigs (the "Glascote Herd"), which retained a pure Essex bloodline despite being officially registered as British Saddlebacks