Grand slam forbidden
A move that would take every enemy seed is not offered at all.
This variant solves the same problem by removing the move. If a sow would capture everything your opponent has, it is illegal and the board will not let you play it.
That is sharper than it sounds. With your opponent down to two or three occupied pits, several of your natural moves can vanish at once and you may be pushed into one you would never choose. Players who like this version say it makes the endgame more precise: you have to arrange things so that one seed always survives.