You could try making a non-rolling treat dispenser from the centre of a toilet roll. Pinch one end flat, fold it over to seal it, add your treats, and then pinch the other end flat and fold over. The second fold needs to be at a right angle to the first, so you end up with a triangular tube like this. Bodge holes in it until the appropriate amount of treat comes out when an appropriate amount of force is applied.
Whether you need more than one would depend on how nicely they play with it. Shoving and shouting and dirty looks are fine, pecking is not.
Whether you need more than one would depend on how nicely they play with it. Shoving and shouting and dirty looks are fine, pecking is not.