Well crap..force your vet to refer you to them then...you don't have time to loose another one for them to autopsy to find out..they need to tell you what's going on.
K-Ro..have you tried the cultured yogurts on them? replenishing the good bacteria? Sounds to me like their immune system is compromised to where they can't fight this. Bacterial or poisoning, they'd need their good bacteria built back up.
You know what I'd do? I'd hit them real hard with a big dose of vit A,D and E, and then hit them every hour with thiamine (big doses--double the dose, even triple it), and then come right back with fortified b-complex every hour as well..(again big doses)..around the clock..push the vitamins, vit. C even..push it in them. Apparently their entire system is thrown off and not able to reproduce itself..the vitamins would supplement what they need, and keep it built up to where they could maintain.
I do that along with what you're already doing. I know you've done it already..but I'd check your hay..and I'd take it in to be analyzed and make sure some type of fertilizer or preservative wasn't used on it that isn't good for goats.
The other thing, your goats are showing symptoms of what I had happen with the distillers grain..our vet faught for 3 weeks to get our entire herd through that, and they too kept eating but the massive diarrhea was awful..my Vet told me they were poisoned too..and when she took samples of our grain (and we had just gotten 3000 pounds of grain--from a substitute feed mill as our mill was down for maintainance and upgrades), hay, and our water..she found the distillers grain, and I told her I never ordered that in my feed. That feed mill got to pay for my Vet bill as well as take back all that stuff they milled for me, and mill "my" feed mix the way I told them to..their excuse was "we lost your feed mix"..well then they should have called me!!