All mine eat TOTW too. My littlest guy (3 lbs) who has the littlest mouth has no troubles. He takes a piece, runs off, crunches it to smithereens, and then returns for another.
Softening it with water or just breaking it up a bit will probably help. This is a much better food than Iams and I'd hate to see you switch back simply because of that.
Many of the top end dog foods make a "small bite" formula. If you don't want to be bothered with crushing it or softening it with water.