Don't worry we'll do that and still do things like this

Feedback, is a common practice used in the pork industry where infected deceased pigs and their manure are fed to breeding pigs. It it also called controlled oral exposure or sometimes oral controlled exposure. It is done in an attempt to make the breeding pigs garner some degree of immunity to circulating diseases.[1] There is no standard protocol resulting in some swine researchers calling the procedure potentially risky and noting that it is often done in an unsafe manner.[2][3] The practice has also been criticized by animal welfare and animal rights groups calling it disturbing and or unethical.

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However, feedback usage extends beyond diseases where vaccines do not yet exist. In 2012, while 45% of large US herds vaccinated young female pigs against PRRS, 26.6% used feedback (or did so in addition).[6]

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The usage of feedback is not limited to just one country or region. Widespread usage has been recorded in at least the 2010s in places such as the United States,[6] Taiwan,[7] Belgium,[8] Japan,[9] South Korea,[10] Thailand,[11] and more. Additionally, following a PEDv outbreak in the 1970s, feedback was commonly used across Europe.[12]

https://en.wikipedia.org/wiki/Feedback_(pork_industry)