You win some, you lose some. The lines of blacks I keep are notorious for being hard to hatch. If I get a chick here, a chick there, I'm happy. Eventually I'll get better at it, figure them out.
I just put together a new kind of hatcher, using a styrofoam ice chest, an Incukit, a hydrostat and a Reptifogger. A simple build, but seems to be very efficient. Temps are dead on. Still need to check my humidity with a calibrated hygrometer. Lockdown on the first bunch is 3 days away.