Cannot transfer specific horses

I was transferring a bunch of Arabians on my spare account and noticed I cannot transfer these 4 foals:

http://equiverse.com/horse.php?id=582302
http://equiverse.com/horse.php?id=582304
http://equiverse.com/horse.php?id=582305
http://equiverse.com/horse.php?id=582303

At the bottom it says:
Trade Horse
This horse is currently in an auction, for sale, or for stud - you can't trade it!

They are not in an auction, they are not for sale and they're too young to stud, so I don't know what's wrong with them. I've transferred like 20 horses to my spare account today, so the account is fine.

I'm thinking, these 4 were the ones that weren't born when that bug hit so that might have something to do with it.

Ideas?

Update: Seems to be related to the blue heart bug.

Solution: If you have a foal you cannot transfer, wait for them to turn three. They'll have a blue heart next to their name. Put them up for stud, then take them down. Horse should now be transferable!