make sure the temp is consistant, 99.6 -99.8..keep the humidity at 60% to 65% until lockdown, then up it to about 75% or so for the hatch. Candle them after 7 days (i'm assuming you have an automatic turner as I do) get rid of the eggs that aren't forming. Basically with Mandarins you just have to try not to handle them too much..don't candle them a ton..be patient and turn and wait and they should hatch. I have some in my bator right now..the hatch rate isn't quite as good as with the hardier breeds like pekin but with mandarins i have about 70%...other breeds i'm at about 90%..so it's not horrible..but mandarins are a fragile breed..so make sure you're incubator is clean before you put them in, and try not to open the incubator a bunch.