Retiring Your Wolf

So I don't know if chat is down or if it's my stupid internet, but I can't ask chat so hello. 

Can we replace our lead wolves with pups? I know the stud can only be replaced with an adult so is it the same for lead wolves? Or can we assign a pup as replacer and the pup instantly ages up?

If you replace your lead with a pup they will age up to 1 year.