We had problems with temp and humidity until we got a Sportsman. Always had low hatch rate with the Hovibators. Had one with the fan and turner and one without. Avgd about 20% hatch rate. I know it was humidity problems. The Sportsman is pretty much idiot proof which is what we need. Cost a lot though. It was a hard decision.
I had such bad hatches a couple years back that I filled my bator with all my own eggs and every last one hatched. Then I knew it wasn't me and my ineptitude.
The problem may not be with your technique or the bator, but with the shipping. If they got x- rays in transit then nothing will hatch. (That's my understanding anyway.) And with the post office holiday rush and the freezing weather, that might have also contributed to your hatch problems...
This was a new incubator to you right? I've noticed that both of mine have their own set of "issues" I didn't see coming. It took me several days to figure them out. And multiple posts on the forums...and multiple PM's...
My still air has temp spikes and drops and my Brinsea, has temperature that is astoundingly even, but the humidity has taken me a while to figure out. (My problem, not the incubator)
I just started hatching so I think the next time I will do some local eggs and see if I can get a better hatch rate myself. (I got 5 hatches total out of 2 dozen eggs (each dozen from a different shipped source) and one died. (So really 4 out of 24.)
If you have a source of fertile eggs I say Go for it! Then you will be able to rule out the eggs, which is a good start.
Thru research I've conducted on the USPS... (I have some good folks working our local PO) they will talk to me about other Post offices in the country... I voiced my concerns about some postal depots X-Raying packages clearly marked "Hatching Eggs"... and as a matter of fact, I've had a couple of customers up in Mo. that had probs with their hatch, while customers down in Ga. Fla. Ala. Tx. were having excellent hatches. The folks at my local PO told me that there were a couple of Postal Depots up in the midwest that x-rays every package, no matter how they are marked... They also informed me that there were more thru-out the country that did the same! They suggested that I learn, (thru trial & error) what parts of the country that I can ship with greater success! That's sad ain't it? There are several postal depots not friendly to our hatching eggs!
My first try with my new incubator was with a dozen shipped eggs that I purchased off EBAY. Zero hatch and I was very disappointed. Gabbard Farms shipped the eggs on a Saturday which I thought was odd and then I didn't receive them until the following Wednesday. I think the eggs had two strikes against them before even I got them home.
I hate the fact that the PO is basically destroying something that is alive. I'm not saying I will never order eggs thru the mail again but I sure don't want too.
My second try was with my own eggs and got nine out of twelve, I believe two were not fertilized because they were clear on day 18.
you know in 45 years I have never been able to tell if an egg was fertile when I first pick it up and I don't sit outside and watch the roos to find out if they have done their jobs or not, and even if I was to sit and watch to make sure the roos was doing his job doesn't mean he did his job right. if someone told you they were fertile when they sold them to you didn't know if they were fertile or not and I never sell eggs if I give eggs to friends for incubating I tell them to come back for more if they are infertile. I have only sold chicks and laying pullets.
I have 5 people around me with-in an hour drive if I want eggs so I can sell unrelated cockerels and pullets I am sure it is the same near you and if you get unfertile eggs from them more then likely if you tell them they will replace them for free the next time you are near them, you will almost never get that online