So I'm sure I am driving you all nuts with this topic (I know my club is about to shoot me

) but at what age should I start to be concerned if Mauser's ears aren't standing? He is a 12 week old German Shepherd...One ear is sort of standing with that whole "comb over" look and the other one is still a floppy pia...At what point (if any) should I be concerned...and/or does anyone have any suggestions or recomendations on things I can do to encourage the ears up?
Thanks a bunch!