@ZoeLGriffiths Go for it! Mrs L-P taught me a good one:
(Let CDD stand for 'cock-a-doodle-doodle-doo')

Let's count back in 1s from 10,
CDD
10,9,8,7
CDD
6,5,4,3
CDD
2 and 1 and don't forget the zero!
CDD

(Repeat for 2s from 20, etc)