My rooster has a big ole curly toe, too. He was hatched that way and there are many theories as to why this happens. Genetics, hatching techniques have been blamed for this. Chickens, unlike parrots, don't grip with their toes. Chickens evolved to be ground dwellers-that is they spend most of their life on the ground eating, drinking, mating, raising their young and so forth. Roosting at night is a survival behavior designed to keep them from getting eaten at night. Even while roosting, chickens don't bend their toes to grip their perch. They spend the night with hocks locked in place while they somehow balance while sleeping with one eye open. Those toes are designed to be rakes that spend lots of time scratching the ground in the search for food.
From what I see in the picture, everything else appears to be in good shape. The only thing you have to worry about is the toenail growing at a funky angle and you might need to trim it every so often. While this is an unsightly defect, your chicken will be able to live a normal life.