I candled all the eggs again at day 10 (Friday night) and it was lovely to see the little chicks moving around. I didn't get any good pictures, but the best way to see for yourself is to look at the day 10 candling videos on YouTube.
Thankfully, it looks like we have only lost 3 out of the 21 eggs so far! The other 18 are developing nicely. Yesterday we checked the 3 bad ones again, just to be sure, and removed them and the infertile (shop-bought) eggs at the same time.
So, we could be in for a good hatch! It's getting closer - only 6 more days until we take the eggs off the auto-turner and increase the humidity levels in the incubator. We're looking into brooder boxes and heating solutions now. Oh, and we need special food, and some little dishes, and bedding and, of course, a fully charged camera battery! :)