[Trillium]

Maybe it's different in the UK, but over here mash and pellets cost the same. Older birds tended to fling mash around too much and wasted it, so pellets turned out to be even more economical. Eventually adult birds hated mash if I couldn't get hold of pellets.

[si-mate]

Mash and pellets should cost the same. I guess that any extra cost in the manufacture of pellets would be countered by the economies of scale as pellets usually out sell mash by probably 50:1