i'm new and have a question

I always see a bunch of puppies being sold at the Trading Center. I have a bunch of puppies I want to sell (mostly because i don't like how they look), but it doesn't give me the option to sell them. I can only sell adolescents!!

Example of puppy being sold

What I see when i try to sell a puppy

If anyone can help i'd be so grateful!!

The puppeis you have aren't old enough to be sold. Puppies need to be 2½ months before you can sell them.

Alright thank you!!