Ag Web has a terrific article about how farmers are using different ways to move toward carbon-neutral production; in this article, specifically livestock (pig, chicken, cow). The pork industry is looking toward a carbon-neutral pig by 2035 and the cattle industry is looking at 2050.
See also (long read):
Pork production in the US contributes more than $23B to the economy, about 25% of which is exported and accounts for less than 1/2 of 1% of greenhouse gas emissions. Yet the pork industry continues to seek ways to improve efficiencies and reduce production resource needs.