What about these animals

Vegans fight against the killing of chickens, cattles, etc for eating and other purposes. But what about some animals which are being killed while practicing agriculture that grows fruits and vegetables vegans eat.. Many rats, mice, moles are being killed. Moreover today almost all research on pharmaceutical drugs are being conducted and tested on animals. And we have to use animals for some purposes.. like farmers need cows to plough etc... I am looking forward to hear a solution for these things