A group of wild turkeys forage on cow manure recently spread over the field (those brown lines in the foreground), probably for the undigested corn from the cattle’s feed.
There’s a whole science to minimizing the cost of feeding cows, including harvesting the corn when kernels are at their peak maturity, decreasing the particle size of the corn kernels when ground, or using a bacterial inoculant in the silage to maximize fermentation (from an article here, thanks Google). My guess is that the small farmers in the area don’t really concern themselves much with those economics, probably for the same reasons we put up bird feeders in our back yard.
There’s a nice article here on the conservation effort over the past century that brought the turkey population in the US back from thirty thousand to seven million.