the patron saint of swineherds, to whom one of each litter was usually vowed. Hence pop. Anthony = the smallest pig of a litter.
1662. Fuller, Worthies, II. 56 (D.). He will follow him like a St. Anthonys Pig. St. Anthonie is notoriously known for the Patron of hogs, having a Pig for his Page in all pictures.
1753. Chambers, Cycl. Supp., s.v., To do him the greater honour in several places, they [Romanists] keep at common charges a hog denominated St. Anthonys hog.
1867. Standard, 24 May, 3/5. What is an Anthony? The littlest pig, your honour. The little pig is always Anthony.