All of you with ill birds: I know that in my old farmers' books, they talk about using vitamin B on ill birds, and in my products as a natural foor rep, I know a lot of the major liquid nutraceuticals (liquid vitamins, suuuuuper yucky flavors, but really good for you) use mega-doses of plante extracted vitamin B for cold/flu formulas. Perhaps you go get them some vitamin B supplements?
WARNING: Vitamin B tastes NASTY. You'll want to get the Vitamin B from the feed store (in the injectible cattle meds) and inject it into a quarter of a grape. No way a bird will choke it down otherwise.
Also, Vitamin D is our body's natural immunity hormone (yes, literally a hormone-like product! Most folks don't realize this, and seasonal depression is often off-set by taking Vit D, as well as is seasonal illness!) and boosting their intake of it would probably help them fight their colds. Many times we lean on antibiotics, but most colds are actually viruses, which aren't affected by antibiotics. What may help them fight them off on their own would be to boost the Vitamin D they have to work with, which will be less this time of year because our ability to make it is diminished with the shorter hours of daylight. If you go get some of that "Emergen-C" stuff that comes in little envelopes to make a fizzy vitamin drink (found at Wally-World, etc) and dump 2 in each gallon waterer, it not only boosts the Vitamin D, but also Vitamin C. The C is citric acid, which will inhibit any virus from being transmitted through the water, a it will be acidic. DO NOT add these to any metal waterers, as vinegar, AVC, Vit C, and anything acidic will break down the Zinc coating on the waterers, causing them to leach Zinc into the water, which can poison them. Use plastic if you are going to supplement them with vitamins. ALSO: to boost the Vitamin D, you have to make sure you're not getting the version of EmergenC that is just C.
NOW: you can also use natural treats to do these things, but it requires giving them greens: kale, turnip greens, chard, spinach, mustard greens, etc. I get the discarded stuff from the grocery store and rubberband it upside down to the side of the run and let them tear at it. It takes a HECK of a lot more of the greens to boost their vitamin levels, though. I do a bit of both to prevent illness. You can also add a splash of Oxine to their water each time to kill all viruses and bacteria so they don't transmit it between one another. Keeps the waterers from growing bacterial slime, too. Safe for use in this manner per label.
I add 3% alfalfa meal to the feed this time of year because of the lack of grass grazing they have, but it's not the same sort of Vitamin D boost.
I have heard that cranberries help them fight virus, and I include it in my feed, but I think it may only be seasonal after this winter- it's very expensive. I also know that garlic is clinically proven to decrease opportunistic viruses and bacterial colds, so you may consider using dried minced garlic in your feed as a top-dressing with cayenne, which helps to fight internal parasites (also clinically proven). Cayenne seems to get them laying better this time of year, too, or you can use crushed red chilies.
Hope everyone is getting this mild temp today...I don't dig the greyness of it, but like that it's not bitter cold.