Thanks for the quick reply. I would say that the bad feed can be part of this. The thing is for every bit of bad you see, there are spores that you can't see. So when feed goes bad like that, it's best just to scrap the whole lot, clean out the container (vacuum it if yours holds 300lbs like mine), wipe the interior with white vinegar and let that dry. The vinegar helps to kill the mildew spores without effecting anything. It's safe. Then replace the feed with new feed.
So it's possible, particularly as there was corn in there, that they're experiencing one of a number of things. First, some remaining mycotoxicosis and/or the oil-vitamin deficiencies that come from that. In addition to that, using scratch as a feed probably decreased their nutrition. So the cumulative effects of both could very well result in illness and death. Birds are particularly adept at hiding illness until it's very bad as that's what keeps them safe. Another potential issue is aflatoxicosis from the corn in the scratch. It's basically about the same as basic mycotoxicosis (from various fungi).
The toxins don't leave their body easily, and they can cause organ issues, increased susceptibility to heat stress (and death), paralysis, vitamin deficiencies, calcium absorbtion inhibition, etc.
So as we dont' really know what's going on, I'd take the conservative approach. First, I'd consider replacing the feed you have if you're low. At the least, when it's time to get new feed do the vinegar wipe of the feeder. If you can, keep the rubbermaid container lifted off the ground on a pallet or something. Then I'd add activated feed type charcoal to the feed of your birds as a supplement for a while. It doesn't take much, but it's a good method of helping in non-specific toxicosis.
Specifically for mycotoxins and aflatoxins, you want to supplement all birds for oil vitamins, minerals (particularly selenium of a certain type and certain amount), fats and proteins. You will want to treat your whole flock.
One easy way of doing this would be to use fortified wheat germ oil (read the label, it's available at
TSC and some feedstores that cater to horses/cattle) in a spray bottle and spray it on top of the feed immediately when served. I would do this daily for 1 weeks and then taper off for a week. Then you can just use it as needed as a healthy ADE supplement. On the week that you taper off, use a total vitamin/mineral supplement in their water on the alternate days. Then use weekly for 2 weeks.
I would give all of your birds a one time treatment with vitamin E/selenium. Use only a human supplement for this. E can be somewhere between 400-700 IU oil capsule. Selenium needs to be less than 50 micrograms per capsule or tablet. (Micrograms are denoted as ug or mcg, not mg). If it's a combination and oil capsule, that's your best bet. But if it's a tablet, that's ok. There's a commonly made vitamin that is 400 IU E/50 mcg Sel. Again use only one time, half of that for chicks.
For the rest of the week, use a regular 400-700 IU vitamin E oil capsule. Slit the end of the capsule, give 2 drops to the full capsule depending on the size of the bird.
So again for the whole flock: Fortified wheat germ oil sprayed on the feed daily for one week, every other day for a second week.
Vitamins/minerals in the water on the 2nd week on the days where you don't give the wheat germ oil.
A one time in-the-beak treatment with vitamin E/selenium for all birds.
For any acutely ill birds, I'd do all of the above as well, repeating the E/selenium if they become ill but only once. For the rest of the week I'd use a straight vitamin E capsule, from 2 drops to the entire contents of one capsule in the beak daily for a week and then taper off. I'd add yogurt during the week, and make sure they're on complete feed - no grains. If they don't eat much, I'd use polyvisol vitamins 3 drops in the beak daily in stead of the wheat germ oil.
This will not hurt any birds that aren't sick, will boost immune systems. This is the treatment for any time you see anything that you suspect to be neurological, note.
On your pyrethrin, I personally prefer permethrins as I'm aware of their safety when used with poultry. If the dust you're using is labeled for poultry bedding, then you could use it. Avoid Sevin. DE is fine -IF AND ONLY IF you use human food grade. Use sparingly.
Added: Just wanted to add that we're still looking for other things. But we want to treat to rule this out since the treatment is effective for other birds as well. Still need to know droppings, weights, rule out parasites, etc etc.