Final answer:
Option 2 best describes the sustainable environmental change for livestock: moving from barns to open range. This method aligns with sustainable farming objectives by supporting animal welfare and reducing environmental impact.
Step-by-step explanation:
The type of environmental change that the livestock will experience from a farmer switching to a more sustainable way of raising them can best be described by option 2: The livestock currently live in barns, and they will be let into an open range to make their lifestyle more sustainable. This shift towards more sustainable practices often involves moving animals from confined spaces to more natural settings, like open ranges, where they can graze freely. This method can reduce the need for additional feed, foster better health for the livestock, and reduce the environmental impact by potentially lowering greenhouse gas emissions, decreasing energy use, and minimizing the strain on habitats.