PLEASE USE YOUR FULL NAME OR THE POST WILL BE DELETED. INAPPROPRIATE LANGUAGE WILL GET YOU BANNED. PLEASE BE CONSCIOUS THAT THESE ARE PUBLIC POSTS. PLEASE BE CONSIDERATE OF CHILDREN THAT MAY BE SIGNED ON.
I don't know if this would be any help in identifying the toxin, but I had a dog that the vet suspected got into some poison. She did a CBC/major blood panel. There were some high values, so she called the ASPCA Poison Control Center and gave them the results. They were able to rule out definitively over the phone that it wasn't poison. If it had been some kind of poison, they would've been able to determine what it was based on the blood values.
I can't remember how long it took for the vet to do the blood panel. Maybe half an hour? And she was on the phone with Poison Control for about that long. I do remember how much it cost, though: $94 for the bloodwork, $65 for the consult with Poison Control.
I'm sorry about your hounds. Hope everything works out okay.