What can I purchase that is a vitamin AND mineral supplement? One of the issues I've run into is dosage of medications for my bitties...most dosage amounts are listed for LF, some for bantams...but we're talking about a one pound chicken.
Half dose should be safe enough. Or a bit less if you're concerned about that.
Eggcessive or some others who use premixed supplements and live in the same country as you should be able to assist you with good brands. I use natural supplements instead, directly provided via their natural source in food. Kelp, generally, is one mainstay I use. Hardboiled egg is another great food for sick chooks, very nutritious and supplies most things they need while convalescing.
I don't even know if the vitamins I'm administering is too much or too little...I really am guessing here. I do not know if you can overdose a chicken on vitamins.
Yes, you can, but if it's free choice it's much harder to do. Given the vitamins listed, and the dosages, I don't think you need to worry.
I've been giving him 0.5 ml's of each daily...maybe I should bump it up to 0.5 ml's of each 2x a day?
I would try that.
I would also supplement the vitamin C more in particular, perhaps through food so it arrives in its correct complex, or via ascorbic acid if that's easier. It's vitally important to healing a lot of issues, particularly viral ones, but also rebuilding tissue.
The body generates hydrogen peroxide to deal with pathogens and health issues in general and vitamin C in the body provides that in larger dose than those animals which manufacture their own vit C can create; this causes a boost of intracellular oxygenation basically, which is anti everything that's anti life, whether cancer, viruses, pathogenic bacteria, parasites, fungi, or toxins natural or artificial. It's quite amazing; you can even use it against snakebite, some vets keep injectable vit C on hand for that reason but at a pinch oral liquid vit C, dissolved tablets for example, will do the job too. An overdose or 'megadose' (several thousand mgs) of vit C (which may give them temporary diarrhea at worst, pretty much) has saved many lives from many things. I consider it an essential part of my emergency kit, which I'm sure sounds weird to some, but the results speak for themselves.
If you can offer him some dark leafy greens it could help with a lot of problems as well as the C. A simple source of calcium is finely crushed eggshell, doesn't have to be that fine though, he'll just absorb it quicker if it is. You can just give that to him straight with a hardboiled egg if you prefer. A good quality protein source is of great importance for healing. He shouldn't be getting most of his vitamins from the premix of course.
What else is he eating, if he's eating at all now?
I really need a plan here...should I start with a wormer first? I have Wazine and Ivermectin injectible (of course I dose topically). I have a Southern States nearby, so I can pick up other stuff if need be...IF they have it in stock. Can I continue giving vitamins while worming? Or continue with just the vitamins?
I've not used chemical wormers on chooks myself so can't advise there, sorry, but I talk with many people that do, and I haven't heard any of them withholding supplements or normal feeds from their chooks while worming.
If vitamins, how long should I be giving them to him, how often, and how much?
I have never used premixed vitamins/minerals like that for chooks, so I can't advise you there either, sorry. I used natural sources to supplement, not isolates or synthetics.
Animals that are unwell tend to go through higher doses of some usual nutrients, particularly A, C, B family, D, E, Sulfur, Magnesium plus Calcium, Copper, Zinc, and some others depending on what's wrong. The ones I mentioned specifically are directly involved in healing from most things, and in combating most things; they support the immune system the most and are depleted the most during the majority of health battles. Your premix isn't offering some important nutrients. Just about anything wider spectrum should help more.
Generally you won't need to worry about overdosing, if it's free choice. He should stop when he feels he's had enough. I don't know how you're giving this to him, I assume via mouth rather than free choice in water? It would be possibly a better idea to give him both fresh and supplemented water and let him choose how much he wants of each.
As for sunlight, no. Only through the window, which the cage is right up against. I put him outside a few minutes ago...in a movable run.
That's good, it can be very helpful to have real sunlight and greens if possible. Also to trigger instincts, give the chook some stimulation, they can get depressed indoors. Some chooks just do not heal indoors, getting them outdoors is necessary.
You mention you have experience with Avian Leucosis... But there are a few forms of it and they behave differently. I have had two, one which affected them young and rapidly and one that affected them only slowly and at much older ages. Both inherited via the egg as far as I know, both strictly expressed within certain family lines.
The latter type did end up with them looking like your rooster. The former type was more like Marek's in symptoms. There's a chance that either of those still might be what's wrong, but I hope not. But symptom lists are guidelines, not every animal shows the exact symptoms expected and some show aberrant, atypical or no symptoms.
Good luck to your chook.