>>40648057
Everything counts.
Every creature you kill, or cause to be killed, places a Karmic burden upon you. The Karmic burdens inherent factory farming are especially heavy, due to the conditions suffered by the animals before their slaughter. This leads to humans becoming very ill, and shortens the lifespan.
Note that there is also some Karma involved in killing plants, but as they are not sentient, it is so small as to be of no practical importance to ordinary human life.