Used sing this at school and into my teens. From the printed verses above you appear to have omitted the Pie Bird, the one with the triangular arse hole that flies across the desert shitting pyramids.

If memory serves me right the introduction started with a recittation something like;

Roll up ladies, roll up gents
See the greatest show in tents
See the leopard's 100 spots
99 on his back and one on his...

Cock your eyes over here folks etc etc, can't remember the rest