To clarify: I don't think either is a "fugly" horse. I think this is a good exercise in evaluating two mares. I'm also going to make a point when we are done about how you can't judge quality by circumstances.


Now that everybody's had a chance to comment, I personally like the liver chestnut better - but I can see some good arguments for the bay. It depends on which conformation faults you personally think are a bigger deal - and that does, typically, have something to do with the discipline you're involved in, which is why I mentioned it.
I like the chestnut mare's hip and she has an ideal shoulder angle. Both mares are posed badly. The chestnut is posed so that she looks like she has a huge head, and the picture was taken looking down, which is never a good idea. The bay is posed awkwardly with her head up and standing in a way that makes it hard to judge her back end. The bay is a bit more compact, which I like, but her hip can't hold a candle to the chestnut's. Also, the bay is a little straight in the shoulder though, yes, some of that look is caused by the way she is standing. She is very deep through the heart, which I love. What I would really like to do for a broodmare would be to put the bay's front end - perhaps with a little more shoulder slope - with the chestnut's hip!
By the way - yes, I know that I didn't give anybody pedigree information or other background. It was simply meant to be an exercise in evaluating conformation, and I was curious to see the comments. It was not a trick question designed so I could jump on you and go "aha, you never asked if _____" and "I wouldn't breed either one!" was a valid answer but not the only "right" answer. There actually wasn't a right answer. This was merely a discussion starter.
The other point I was going to make was that circumstances don't dictate quality. Broodmares in particular tend to wind up in bad places if they go a year or two without a baby. That's what happened to the chestnut mare - she was a slaughter rescue. For the money it cost to save her, she would have been a pretty nice mare for a breeder on a budget - but they would have had the eye to pick her out from the herd. She got extremely lucky and has a permanent home where she doesn't have to do anything but eat.