Hajdamach suggests that swans and pigs were the most common form of animal novelty frigger, but since I can't find a pic. of another pig like these - and both Hajdamach and Vincent show only solid examples - have to assume that hollow pieces like these are a lot less than 'common'.
I don't know that you'd say these were showing off the glassmaker's skill, so probably just a whimsey for fun. The seller suggested they would have contained 100's and 1000's or some sort of sweets, although I see that Newman - referring to pigs - says that some were solid, and others used as flasks............perhaps these might have been so used, for a drink of some kind?
Once emptied of their contents, many of the animal and toy examples were apparently played with by children.

Length is about 8.25" (210mm) - height about 4.25" The tail has been used as the connection to the pontil rod - one piece showing a clean sharp break and the other appears to have been fire polished.
Below the bottom jaw there is a small area that has been ground/polished flat - and no idea why, unless the head had been formed separately in some way, perhaps.
Quite a lot of small bubbles and a few stones/seeds.
The slightly pincered trailing across the backs of these pigs it very C19, and I'm sure they're not later (I hope) - but aside from being eighteen something, I'm very unsure of a more accurate date, so hoping someone might have some more details to offer, and thanks for looking.

Ref. 'British Glass 1800 - 1914' Charles R. Hajdamach - 1991
'Nailsea Glass' - Keith Vincent - 1975.