Abhorrence and fear of Haitian immigrants coming to Alabama to fill jobs in poultry plants had been building among conservative residents even before former President Donald Trump jolted the presidential campaign with his outlandish and thoroughly debunked claims that “they’re eating the pets.” But in this state, which Trump carried in 2020 by a 25.5-percent margin, and other parts of the country where new immigrants have made an impression, a conspiracy theory fed by state and local officials is taking hold four weeks out from the Nov. 5 election. The belief that the Biden administration is d…