I am so sorry you are going through this. I'll tell you what i used and you can decide from there. I use a combination of Bird Powder, which I got from Jeffers and a vitamin/electrolite powder I get from TS. I have survivors that are now 8 months old. They are laying and other than the size difference from what they should be, to what they are, they are doing amazingly well. The thing I found is once you start the vitamins don't stop. I found this out the hard way. Now one thing no one has ever been able to explain....my Dark Cornish, who were in this group, were the least affected. I lost 2 of them, out of 10 birds and the regular chickens, wyandottes, JG, WR, PR, BJG, etc., all but 100% mortality. All but the partridge rock were immunized for Marek's. Didn't matter. Most of them got it and died. There is something about the game birds that helps them. I'm not smart enough to know what it is, just that it is.