Pigs might vary from RM to RM in Saskatchewan as to status as livestock or pest, but they are never a big game animal so legally there are no problems with ammo types. Big game needs an expanding bullets. Coyotes are either a pest or a furbearer depending on who's shooting and where its standing so FMJ are legal. While we're at it bears are either a big-game animal, fur-bearer or pest depending on who and where the shooting is being done by, but legally they require expanding bullets.
That's the legality, but the bigger question is why would you want to use the FMJs? They aren't good for much, unless you never want to see the animal again.