
Breeding barn studs not being hired by AI
I have the top Stud (ranked by career earnings) in the breeding barn, and 3 of the top 10, yet not a single AI farm has used any of them for breeding.

Is it just a matter of time and waiting for their offspring with my mares to chart them some offspring career earnings?
Although judging by me horses performance in the online league, maybe the AI knows something I didn't about them.
Also while on the topic: at what age should mares be retired? I had read here that they declines around 13, and I sued to retire them then, but I have one mare who still pops out good foals @16.
Thanks in advance.