Is cross beak a genetic deformity or can other things cause it?

[nzchicke]

excellent- thanks- i wondered if it was to do with the scull and brain too (too much useless stuff comes up when googling I gave up) ..as I had a chick that did not hatch from purchased eggs had- crossed beak and brain hanging out of its scull too

I never kept any of the birds but have a crossbred male and female from a healthy hen from that hatch. they so far have not produced any chicks with problems- it is the other pen so far.