She's young right? I wouldn't kick yourself over 20/20 hindsight... I am not sure you would have thought xrays would have been a needed expense at her age, would you have knowing what you knew then?
What did she do before you got her? Any idea what might have brought on the condition? Is she predisposed for some reason or did she do work hard enough or had poor enough foot care that it might have been prevented?
She's only 10. Her legs and feet look beautiful and she's never had shoes. All she was used for was a trail horse for a timid rider.
I'm not sure what causes navicular. There are some predisposing factors, such as small feet on a big horse but that doesn't apply here so who knows. Another predisposing factor is the horse with the broken back hoof pastern axis with long toe, low heel conformation, something Winnie doesn't have either, but Tuffy does. I'm keeping a close eye on him, that's for sure.