With the Elector, did you buy an 8 ounce bottle yourself, or were you relying on resellers?
I used to buy from resellers, then tried a manufacturers bottle from Valley Vet.
The difference!!!
It even looked different. Like whole milk, white and slightly thick.
What I used to get from resellers was watery and opaque.
How was the Elector stored? It needs protection from UV rays or it goes off quickly.
Elector should be shaken once a month. According to the manufacturer, the active ingredient Spinosad can fall out of suspension, and once it does it is impossible to reincorporate.
If you've seen a batch of Elector that looks separated, it's no good anymore.
What dose did you use? We've used it primarily for Lice, and I use and recommend the larger dose on the label .. 12 ml / gal instead of just the 9 ml proliferated on the internet which is only targeting one kind of mite (I do think it was the Northern, but can't remember).
All this is to say, Elector is a very good product, and I'd be super surprised if a good batch in the stronger dose really doesn't work.
Are you treating all those birds at the same time? Did you spray down the premises to eliminate safe harbor for the bugs?