How are you incubating them? It can be harder to incubate and get surviving chicks in the colder winter months. Roosters can be less fertile and hens reduce laying so that can be hard to get fertile hatching eggs for that reason too.
I had 2 hatch this morning out of 5 with one still chirping in the shell. I had heard the same thing and only tried it because I still had an incubator out. I was surprised and excited to find chicks today, especially since these are my fist pure bred cuckoo marans! Good luck to you. never hurts to give it a try in my opinion.