I candled a few today at day 17, and saw movement in all the ones I looked closely at. It's not the same as it was before - no swimming, more like twitching. I'm a little worried that some of the air sacs still look a little smaler than diagrams I've seen online. Some look textbook, at the fat end of the egg, slanting slightly downward, but some are still almost perfectly circular at the fat end. I'm hoping they'll do some more shrinking in the next 24 hours before I increase the humidity. Thanks for all the great info I'm finding here. That day 19 early pip teaches me why we up the humidity after 18 days.