Suppose we stopped "enhancing sporting opportunities"--manipulating habitats, predators, and herds to produce population explosions for hunters' benefit? This happens in every state in the Union; state and federal wildlife agencies and private farms all do it. I have two file boxes full of documentation. No doubt Google could give many current examples. Any college library has whole stacks of shelves full of studies on the subject. There are courses with textbooks especially written for the purpose.
On the other hand, what does the production of PZP cost the pigs?
Thomas Lee Boles