Backwards pipping

[Knighstar679]

Anyone know what might cause ducklings to pip backwards? Basically the underside of the egg?

I am thinking it has to do with something that changed in my incubation practice. The only major thing I have changed is that I don’t have shelf liner in my incubators that I use for incubation. This means that the turning isn’t always seeming as smooth as they used to look? Could this be a cause, are there other possible causes?
I am incubating in NR 360s

 

[Stipenvlerk]

I'm sorry no one answered.. did they survive?

 

[Knighstar679]

I'm sorry no one answered.. did they survive?

No the two that pipped backwards died. One died while still in the incubator and the other several hours later in the brooder

 

[Stipenvlerk]

No the two that pipped backwards died. One died while still in the incubator and the other several hours later in the brooder

I'm so sorry for your loss...