What Happens to young pigs when they get older? What does Jones do with old dogs?

The young pigs would be butchered.

You young porkers who are sitting in front of me, every one of you will scream your lives out at the block within a year.

The old dogs are drown.

As for the dogs, when they grow old and toothless, Jones ties a brick round their necks and drowns them in the nearest pond.