I haven't used this brand of incubator, but there are mixed reviews on it. I think you have to monitor the temperature and humidity very careful and move eggs around if there are hot and cold spots. Watch those vent plugs too as they chicks can suffocate from lack of oxygen (particularly if it's still air and doesn't have a fan). Hopefully someone who has used this incubator can give you a little more detail on how they've been able to get successful hatches from it! Shipped eggs can also have lots of problems from transport, so usually a 50% hatch is what is expected if all goes well (thought it can be better).