Can I Ask A Question About Cavalier King Charles Spaniel Puppies ? ?

I have a 6month old Cavalier King Charles spaniel who has feathery hair on his feet,tail and ears but not very long.... His body hair is still short. I have a friend with an 8 month old Car and his fur is grown in all over his body.(Mine is also a male). Mine is on the bigger side of Cavs and with great muscle structure and I know he is all Cav because I have his papers. What could be inhibiting the growth of his hair?