why can't any of my draft horses(females) be covered (3)
Drafts can only be covered and cover other drafts 3 times in their lives
Yours have probably already used all their covers and therefore can't produce more foals
Repsonding to "if you have vip then you get extra time"
You're mistaken, that is with donkeys. A certain vip perk allows only vip members to breed donkeys 4 times
As of yet there is no divine nor perk that allows more than 3 draft covers.