Part of your problem may lie in the fact that you're using shipped eggs which as you probably know can sometimes have miserable hatch rates. There's not much you can do about that.
But it sounds as though you're experiencing at least one other problem as well.
Have you calibrated the hygrometer you are measuring your humidity with? I've yet to find one that is dead on and have had some be off by as much as fifteen points.
Also, you mention you live in an arid climate where the humidity in your incubator can be as low as 5% if you don't put any water in. Are you also at a highish altitude? I've read in the past where one fellow was hatching at his home in a high desert. He ran his lockdown humidity at 80% because the ambient humidity and air pressure was so low.
If possible I'd try to get some local eggs from a known good source and hatch them to see what your percentage is. Then I'd calibrate the hygrometer if it hasn't been already then I'd try boosting the humidity. Here in Florida where I am I'd never run it so high because it would simply drown the chicks. But in an arid climate, particularly at high altitude, you may need to in order to keep the chick from being shrink wrapped before it can hatch.
But it sounds as though you're experiencing at least one other problem as well.
Have you calibrated the hygrometer you are measuring your humidity with? I've yet to find one that is dead on and have had some be off by as much as fifteen points.
Also, you mention you live in an arid climate where the humidity in your incubator can be as low as 5% if you don't put any water in. Are you also at a highish altitude? I've read in the past where one fellow was hatching at his home in a high desert. He ran his lockdown humidity at 80% because the ambient humidity and air pressure was so low.
If possible I'd try to get some local eggs from a known good source and hatch them to see what your percentage is. Then I'd calibrate the hygrometer if it hasn't been already then I'd try boosting the humidity. Here in Florida where I am I'd never run it so high because it would simply drown the chicks. But in an arid climate, particularly at high altitude, you may need to in order to keep the chick from being shrink wrapped before it can hatch.