This is my first attempt at incubating. My eggs went on lockdown last Monday and they all looked good as far as I could tell with air cells and dark and veining. Day 21 started Thursday evening into Friday. It's now going into day 23 and no signs of hatching. I'm not even sure of any rocking. I'm curious how long I let them go before throwing in the towel. Are there any ways to tell if the eggs are still alive and if so at what point? Thanks for any advice.