Politicians on Pigs

It seems that politicians of an earlier era referred to pigs quite frequently. For example, Harry S. Truman famously observed that

No man should be allowed to be president who doesn't understand hogs.

Truman grew up on a farm in Missouri, so he had first-hand knowledge of pigs. I've always guessed the same is true about Sir Winston Churchill, who said

I like pigs. Dogs look up to us. Cats look down on us. Pigs treat us as equals.

Perhaps unsurprisingly, it's hard to find authoritative sources for these statements. They both appear all over the place, but by some perverse logic, the more these quotations are reprinted the less likely I am to be able to verify them. I'll keep digging...