I'm not sure whether that's really a monk as the action really cruel!
I can't understand why people couldn't just think of them as just like human which have feelings too.
They have the same mind as we have, and also want happiness, like we do. For example, if you suddenly touch them, they are immediately frightened. They get frightened if somebody beats or hits them with a stick. We also get frightened. If somebody throws cold water on our body, suddenly we feel a shock. It is the same for animals. They have the same mind, and it is very important what happens to them.
Even if they can’t speak, can’t express themselves, animals can show their fear through their body. For example, they try to run away. Human beings can talk and complain, and they can bring court cases. Human beings can report things to the police. Human beings can do so much, but animals can’—they can do nothing. They can’t express their suffering. Human beings can talk about their fears. Whether other people accept your suffering or not, at least you can explain it and the other person can hear. Animals can’t, but you can see how they feel from their movements. If someone tries to attacks them, they run away. They are afraid, which means they want happiness and not suffering. This is a very important point, that they have the same mind as us. If you kill them, you create the negative karma to be like them. For one hundred thousand lifetimes, you will have the karma to be born as an animal. For many thousands of lifetimes, you will suffer the consequences.
It is said in the teachings that if you kill one animal, because of that karma, you will be killed five hundred times by others. You will suffer in very hot hell realm for one thousand eons. It is also good to ask yourself how it would be if somebody killed you with a knife. How would you feel in that situation? For example, if you put your finger in hot water, can you bear that? You can’t bear it. It’s the same when you kill animals. There is no good result from it. There is no question about that.