I've had a number of red bags, all have lived and been normal healthy horses. It's not necessarily a terrible outcome, but time is of the essence. Once you realize you have a red bag, you need to get that foal out and breathing. We do have one mare who may have been a little compromised by oxygen deprivation at birth - one of our first foals, I didn't know a red bag from a paper bag LOL and the vet did not elaborate when I described it. She's been a healthy mare, has given me some nice colts too, but she's never been just quite "right" mentally. Very sweet but very slow and I've wondered if it had to do with birth circumstances. Just a guess, since her dam & siblings are very quick, alert horses.
Jan