Hansen, if you still have 4 days to go, that's way too early to stop turning them. Have you candled them at all? I'm excited to see your babies, I love silver laced wyandottes.
At the beginning of day 19 (so you have all day 19, all day 20, and unknown part of day 21), you should stop turning the eggs, and bring the humidity up to around 65-75% humidity. You don't get to open the incubator or otherwise mess with them during that time, hence the term "lockdown".
So, Whittni, when my eggs were due on a Saturday, my incubator stopped turning on Thursday.