Worms query

Fairly recently working an allotment bit by bit and now able to dig reasonably since we've had some rain. I'm concernend for our worms. We never saw any last year but now with some donkey droppings and stuff they are BIG. While digging I worry and feel guilty that so many get divided.

If, hypothetically, there are 100 worms in a bed when I start to dig and, when I've dug it, every worm is chopped in two, how many worms would there be in the near future? Is it zero because all die or is its 200 'cos tails and heads grow new bits or the same number (100) because pointy ends grow new tails but the tails die (or vice versa) or something else?

I think I like worms because I read that they 'do the digging for you' (up to 1% or 2% of it, perhaps, based on the performance of ours last 9 months to September).