No doubt that a Muslim is required to show mercy and kindness toward all beings. No Muslim is allowed to take pride in causing pain to an animal or any other creature. Prophet Muhammad (peace and blessings be upon him) is reported to have said, “The merciful are shown mercy by the All-Merciful. Show mercy to those on earth, and He Who is in the heavens will show mercy unto you.” (Sunan Abu Daud and Sunan al-Tirmidhi)
In his comment on this issue, Sheikh Mohamed El-Moctar El-Shinqiti, states,
First of all, Muslims do not take pride in the pain of animals because this contradicts the basic teachings of Islam. The Prophet (peace and blessings be upon him) taught Muslims to be kind to animals, and he blamed one of his Companions because he treated his camel mercilessly.
In Islam, animals, just like humans, are considered to be “nations” as Almighty Allah says, [There is not an animal (that lives) on the earth, nor a being that flies on its wings, but (forms part of) communities like you. Nothing have We omitted from the Book, and they (all) shall be gathered to their Lord in the end] (Al-An`am 6:38).
The Prophet indicated that treating the animal kindly could be a reason for one’s admission to Paradise, and that merciless treatment of animals could be a reason for one’s condemnation to Hell. The Prophet gave an example of someone who will be admitted to Paradise because he gave water to a thirsty dog, and another example of a woman who will be sent to Hell because she locked a cat in a cage, without feeding it or letting it go free.
As for slaughtering animals for food, it is natural and permissible as it is one of the reasons of Allah’s creation of animals and one of the ways Allah has honored humans over animals. However, certain conditions must be applied in order for the slaughter to be accepted. The animal must be put to rest before being slaughtered, the means of slaughtering must be sharpened well, the animal cannot be tortured, etc.
All these conditions must be fulfilled in order to make sure the animal is treated kindly and is slaughtered in a proper, merciful way. Whatever means of slaughtering are used, the Muslims must opt for the most merciful method that would cause less pain to the animal. For example, despite the controversy over stunning and other pain-lessening means used in Western countries today, I hope Muslim scholars will look into these modern ways and how much they can be put under the category of merciful treatment of animals before slaughtering, which has been strictly advised by the Prophet (peace and blessings be upon him).