In short, it depends on how you raise them.
The way food conglomerates raise commodity animals (grocery store meats), is bad because the majority of them are raised in CAFOs. CAFO stands for Concentrated Animal Feed Operations. Concentrating animals in one small location is a recipe for disaster. We could go on for days about this (call us anytime and we will), but the simple answer is yes - farm animals can be bad for the environment when they are raised as part of a factory, where they’re pumped with antibiotics and other things that make them grow faster, but also upset their stomachs and cause gas (Co2 emissions). And that’s just one of the issues.
On the other side of the spectrum, pasture-raised animals can actually help the environment by regenerating and fertilizing the soil.