I'm worried about a horse on the livery yard where I keep my horses. I'm not sure if there's anything I can or should do or if I need to keep my nose out of it. I'm usually highly averse to being a livery yard busy body and only venture opinions if they are asked for... And even then am more likely to say something soothing and uncontroversial than venture my real opinion. So actually thinking about taking action about someone else's horse is a reflection of the condition of the horse rather than a general proclivity to interference on my part!
The horse in question is not abandoned or necessarily uncared for... it might be rather too cared for in a sentimental sense but is somewhat lacking in the practical. I know it has received veterinary attention and has serious dental problems and an increased amount of care is being provided to try and improve its condition BUT the treatment it really needs to its teeth is being withheld (cost? The requirement of a long journey to a vet hospital?) and it's condition has worsened to it being basically shockingly thin (as opposed to just moderately skinny). You can see wither and hip bones jutting out even through a rug and all ribs and some spinal further processes without the rug. The thing that's really getting to me is that it has now lost all the hair on its face, like it's just fallen out because the nutritional resources to keep growing it are not there.
It's getting fed but it can't chew or properly digest it.
I'm not on close enough terms with the owners to venture a discussion (It's one of those large yards where you aren't friends with everyone and they aren't in my block) and from what I've seen of them I'm not sure how well received it would be. I am considering a quiet word with the yard owner but the YO themselves have a very old, very thin horse (who is otherwise, however, healthy and happy) and I don't want them to feel judged by proxy! Angering the yard owner is not something I want to risk. I'm not sure phoning the RSPCA is the right thing either. 
I also don't want to watch or feel I have been complicit in a horse dying of starvation.
At the moment I'm waiting and seeing and hoping a bit of spring grass might set it up for a bit. But if it was my horse it would not have ever been allowed to deteriorate to the current point which is I think verging on and most likely actually crossed into being cruel. I understand there would be a reluctance to PTS, of course, but it seems to have overstepped the normal variation I've seen in people of where that line is drawn. I'm hoping they will draw their line soon... perhaps they are also just waiting to see what spring grass will do. The horse has been relatively cheerful but is just starting to look sad and sunken in the last week.
I'm just wondering what would you do? What have you done in similar situations? I would very much rather not involve myself in any way but it's starting to get to the point where my conscience is nagging me.