The one that I had photographed for my fix hatched out of the side of the egg and had a real struggle. I hatched about 80 that batch and 2 hatched from the side, and one had splay and the other curled toes on 1 foot.
In the case of the chick from the OP here, I personally would fix both at once because the window for repair is short, and the sooner you correct it while they’re small and the legs are softer and more malleable, the better chance of total recovery. My splay chick from the photo can’t be distinguished from the other 23 hens now several weeks old. If you had a whole hatch of issues I’d say check your breeding stock, but one out of dozens is probably egg positioning, as this chick seemed to hatch with the leg already sideways from the egg. I hatched probably over 1000 eggs last year, and had maybe 3-4 splays, and a few curled toes from my homegrowns.
I did order eggs, which hatched with multiple splays, curled toes, crossed legs, etc, and then I lost several over the first week to slipped tendons. Someone I know in vet school told me that was classic signs of poor nutrition in the parents. My next generation of the survivors bred to my home growns had no defects at all in about 150 chicks. So I tend to think the nutrition of the original parents did play a part.