My guess is that, if it's small enough to go in, it's small enough to come out

Fruit pits are generally a dump spot for anything the fruit doesn't want. They generally contain a bunch of waste toxins, leftover chemicals, etc. It's not really ever something that one would want to consume.

As far as my 10 gram parrot, he would get very ill or die from eating a fruit pit. I have to remove them. I'm unsure about pigs but I suspect they are capable of consuming them in at least a reasonable amount.

Give Bacon and Eggs a pat on the head for me. Nom-nom-nom.