@Saaniya is located in India, and is a vet student I believe. She has been helpful offering advice about where to find medications and what feeds to use.
Your cockerels problem could be hereditary, infectious disease or dietary related, but Mareks disease should also be considered. A complete balanced chicken feed or diet is best with 20% protein from hatch. Chicks who do not thrive early with a good diet should be treated for possible coccidiosis with amprollium or sulfa antibiotics. The chick’s foot and legs look irritated from lack of or soiled beeding, and early bumblefoot and joint irritation is seen.
What are you feeding now? Pictures of the chick standing normally would be good. A chick chair or sling might be helpful if he cannot stand or walk. Here are some examples:
https://www.backyardchickens.com/threads/versions-of-chick-chairs-please.1166308/
Thanks for mentioning
Earlier when I talked her about her rooster puchi who was in same condition she told that she feed oinions which cause avian anemia