You really should ask her (or call her to ask) why she wants another filly when she's doing nothing with the other two. I don't know if you guys are friend's or if you don't want to hurt her feelings, but I'd be arguing with her. You could even print some articles offline about breeding and training young horses to give to her. Or, if the baby still has the lumps, ask her again about them. If she makes up another answer, or keeps the spider bite excuse, you should tell her that it's not possible (if they've been there that long). Although, I'm guessing you've already tried changing her mind, huh? Poor horses. Good luck...