I'm not sure if this is the correct place to post as this isn't exactly your classic horse conformation critique. I see the phrase "back at the knee" used quite frequently in conformation critiques on here and I'm not sure exactly what that means. I tried to search it on google, and I get some pretty descriptive pictures, but most were very exaggerated. I understand the theory of the phrase, but then I'll see a photo of an actual horse that someone says is back at the knee, and I don't really see it. A few months ago, someone on the forum told me my mare Lilly was back at the knee. I've included some pictures of her below. What are the indicators that you look for to determine this? Would you consider this to be a serious conformation fault? What are the possible negative effects for a horse that is back at the knee? Also, in these pictures, Lilly's feet are not the best; she missed her regular farrier appointment due to a serious abscess that prevented her from bearing weight on her front left. Could just not having her feet trimmed cause her to go back on the knee?
I know I ask a bajillion questions, so I appreciate everyone's time and input on here! I hope everyone has a Merry Christmas!