Just got a new horse on Tuesday from a Rescue. She was already thin but doing well. Brought her home and the other horses are being mean through the fence. So she stressed. She will eat some grain but she will barely eat any hay. She is in the corral so the other horses can't bully her but can smell her over the fence. Any suggestions on how to get her eating better. She can't afford to loose any weight.
Is there a spot where she prefers to stand? Hang a hay bag there. If you have the option of putting her in a stall for part of the day, she may feel more secure there. A horse going off its feed briefly in a new and stressful situation, however, is not all that unusual and usually they will not voluntarily starve themselves to death.
Maybe consider a course of omeprazole or ranitidine in case the stress and poor nutrition have gotten her a crop of ulcers.
A senior or complete feed (the kind meant for horses with poor teeth--lots of fiber) can often tempt animals that don't have a great appetite without loading them up on feed that's super concentrated.
I know you said her teeth are fine, but it might be worth checking them again. I bought a project horse one time a few years ago. She had just had her teeth done two weeks before I got her (by the same dentist that I use). She ate her hay fine for 1 1/2 days then completely stopped eating hay. No other symptoms. She ended up having a split tooth that must have happened since her teeth were done just too weeks before. Just an idea.