Eggs have a Knick on top

[Zwillingsmama]

I have 5 chicken. Recently I find eggs with a small knick on top. The strange thing it’s always the egg from my BCM. I would guess it’s every other egg she lays. Any idea why. She is 2 but until about 2 weeks ago I never had a problem. Nothing has changed, same coop, nesting box, food, flock.....

 

[BZZB]

One of mine also started to do that recently she's a barred rock and is about 3 years. I've never had an issue with her doing that before.

 

[rosemarythyme]

Are the shells on her eggs thinner than the others, or thin in that area of the egg?

Are the nest boxes all well padded? Mine sure love kicking nesting material out of the way but the bottom still has padding to reduce issues with cracking.