Older foals can be placed in the nursery or can be grown by using FC. To figure out what your foal/calf will grow into using the nursery, place the foal or calf in the nursery, look inside, and hover you cursor over the baby. There should be a popup showing you what the advlt version will be. If you use FC the foal/calf will grow into the advlt counterpart. For example, the Autumn foal will grow into an Autumn horse. Newer foals and calves (ones released after the paddock) will not go into the nursery and can only be grown using FC.
If you wish to debate the pricing of calves and foals, please use Discussions or Feedback forums. This forum is strictly for users to ask and answer game related questions.
Since the OP's question has been answered and this thread has gone way off topic, I'm closing the thread now.