Smirks is very lucky - that is a slight crook - and it looks like both top an bottom went that way.
Mine had a straight bottom beak - and the top curled over and sideways. I had to cut the bottom off because I was afraid it would curl all the way around the bottom and make it impossible for it to eat. However, I think the crookedness on mine was reflected somehow in her skull - because she always acted "odd".
I know its much more complex than that because Partridge is not just a gene - but this would be a very simplified version. They can also grow up to look like regular Blue, or Black, or Buff or whatever - but still create Partridge looking chicks.