Hi there, don't take this the wrong way and I'm not not trying to be mean/rude but please, please don't tell people you're homeschooled when researching topics like this, it feeds the stereotype that many people have.
Anyway.
Amprolium is just a thiamine (Vitamin B) inhibitor (blocker). It's...
A state vet can do it, or the closest Agricultural college. There's a list around here that has them. One moment , let me find it.
https://www.metzerfarms.com/poultry-labs.html
The percentage isn't set by "big ag", it's simple the most economical percentage for egg production on a large scale. Up until the last 10 years, there wasn't more than 4 option for feeding chickens, there simply wasn't any research and advancement in that area. Keeping chickens for longevity is...
Standard procedure is an all flock or chick feed with oyster shell on the side, though with their size, an aviary calcium grit might be better.
My polishes get an ornamental crumb from nutrena, it might be good for serama as well.
Nothing you feed will make them lay and you want them to take...
I don't think k chickens can smell that well. Both the deer and elk ate our mint beds down so I'm not sure how well they'd work. I wouldn't worry about toxic effects from either product.
What repllent are you considering?
My neighbor used coyote urine and a pellet gun.
We have the same issue with elk here, people feed them so now we have giant hormonal deer that arent afraid of people and can kill you.