I find it kind of annoying to see the message:
"Your stud request to my lion was rejected. You received the stud fees back."
without telling you which lioness you had studded was rejected of the studding.

Similar to when your lioness gets pregnant I think a message should show up saying something along the lines of:
"Your stud request to my lion was rejected. (LINK TO LIONESS HERE) was rejected of the studding. You received the stud fees back."
Just for conveniences sake, to make breeding a bit easier.