So long story short I have 1 egg in an incubator (cross AND half bred, parents are Indian runner cross possibly Muscovy? Not sure) and the development of everything was perfect minus the air sac that was slightly too small but not small enough to cause major health issues. The duckling was due Thursday the 14th, it's now the following Sunday. I checked yesterday by candling and there was movement and the veins were almost completely gone, but today I've checked and there doesn't seem to be movement but the duck appears closer to the air sac as I can't see much other than the air sac now. I tested it in water and he floated how he should but I'm not sure if there was movement. The temperature was a constant 37.5 throughout the 28/31 days and the humidity was steady until lockdown (now high humidity) but something has happened, I'm afraid he might have drowned but there's no way for me to tell if he's alive or not. Please help! He's the only survivor.