Early in October I spreaded lots of horse dung on the top of the soil in my
intended potato plot and covered it all with carpet etc. It has been said
here many times that the worms will do their work so I don't really have to
dig it in.
My question is where did the worms come from, there are loads of them even
now when I lift a bit of the covering to have a look. Nice big fat
earthworms and lots of much smaller red worms. The red worms are quite
different from the ones in the compost heap.
I was thinking that they could have come with the dung, if so, how? And
also should I be doing someting about it?

Thanks
Baz