It looks like he is suffering from a leg bone deformity like Valgus Varus, rotated Tibia or similar. As far as I know there is nothing that you can really do to correct it.
I would think the leg will become worse, his level of comfort would diminish and he will have more trouble getting to food/water as he puts on weight.
I had one similar to this. She would hobble around and eat and drink. Really confused me when she died 3 days before processing. Wishing you better luck!
Won't be Cornish hen size until Week 5. They are at Week 3 + 4 days. They get around and eat/drink a ton like the others. No sign of illness or being in pain. Still try to scratch and search around the straw, dust bath and try to challenge the other cockerels that run up to them ( my batch is all cockerels)