I've just been using a screwdriver to poke a hole, then putting the stolon of the chick into it to hold it. I like the idea of the broken pots, though. wonder if I can find some more broken terracotta pots somewhere.
Linda, I'm just doing it random; I like the idea of a pattern, but that's waaay too much thinking for me at the moment! It's going to take me a while...