Just see if you can see any movement, it's okay if you don't see anything though. They rest a lot before hatching. Also look for internal pips. You'll see the beak in the air cells. I'm sure you'll have more hatch!
Hatching could be delayed based on not steady temperature in the incubator. My ducks took 32 days to hatch.. four extra days! If there are no external pips I would open the incubator and candle them.