Dominion, a documentary about the animal agriculture industry, is a brutal and very thorough exploration of these conditions. It's a gut-wrenching watch but everyone who eats meat and buys eggs or milk should know exactly what they are contributing to. I have no problem with eating meat or eggs/animal products in theory, but the industry is horrific and most of these animals will live short and deprived lives.

And obviously you're not bothered by your pets vocalizing in their carriers, they can come out afterward and it's for their own health.