I agree with "Spider" that you would be better removing bottom of
barrel and standing it directly on the soil. I use a plastic dustbin
upside sown with bottom cut out and use lid with brick on top.
It is tnen narrower at top and the bin can easily be removed to start
a fresh "heap".

However if you want to shake, rattle or roll it, you would need a
fitted lid and holes not just in the bottom but up the sides too.

By now you need at least 3 to compare these methods!

Pam in Bristol