Islamically, killing animals without need or intending to gain benefit from them is impermissible and sinful, such as killing or hunting merely for the sake of entertainment and enjoyment.

The Companion Al-Sharid (Allah be pleased with him) relates that he heard the Messenger of Allah (Allah bless him & give him peace) say, “If someone kills a sparrow in futility, it will cry out to Allah Most High on the Day of Judgment saying, ‘O Lord! So-and-so killed me in vain, and did not kill me for any useful purpose.’” (Sunan al-Nasa’i 4446, Sahih Ibn Hibban 5894 and Musnad Ahmad 4/489)

Sayyiduna AbdAllah ibn Amr (Allah be pleased with him) relates from the Messenger of Allah (Allah bless him & give him peace) that he said, “Whoever kills a sparrow or anything above it without a just cause, Allah Most High will hold him accountable on the Day of Judgment.” It was said, “O Messenger of Allah, what is a just cause?” He replied, “That you slaughter it to eat it, and not to simply chop off its head and then throw it away.” (Sunan al-Nasa’i 4445 and Mustadrak al-Hakim 4/233)

A sparrow is among those animals whose meat is Halal to eat if slaughtered properly, thus the Messenger of Allah (Allah bless him & give him peace) prohibited its slaughter if there is no intention to eat its meat. This prohibition is to be extended to all animals – both whose meat is Halal and whose meat is Haram to eat. As such, if there is no useful purpose in killing the animal, such as eating the meat of a Halal animal or benefiting from the body parts of a Haram one, it will remain unlawful to kill it.

Furthermore, it is narrated from AbdAllah ibn Umar (Allah be pleased with him) that he passed by a group of people who had tied up a hen and were shooting at it. When they saw Ibn Umar (Allah be pleased with him), they fled. So Ibn Umar (Allah be pleased with him) said, “Who did this [to the hen]? The Messenger of Allah (Allah bless him & give him peace) cursed those who do this.” And in another version, he said, “Allah curses those who do this. Indeed the Messenger of Allah (Allah bless him & give him peace) cursed those who use anything in which there is a soul as a target.” (Sahih Muslim 1958)

In this Hadith too, there was no apparent benefit to be gained from killing the animal other than target practice. As such, it was considered unlawful (haram).

Likewise, it is sinful to stop feeding an animal and leaving it to starve to death. Sayyiduna AbdAllah ibn Umar (Allah be pleased with him) relates that the Messenger of Allah (Allah bless him & give him peace) said, “A woman was punished for imprisoning a cat until it died, and she entered the fire of Hell because of that. She did not feed it or give it water when she imprisoned it, neither did she leave it free to eat of the pests of the earth.” (Sahih Bukhari and Sahih Muslim 2242)

What if there is a need or benefit?

However, if there is a “genuine need” to kill an animal, then it becomes permitted, such as killing animals and insects which cause harm to one’s self or belongings. The Messenger of Allah (Allah bless him & give him peace) allowed, and in some narrations ordered, the killing of snakes, scorpions, geckos, mice and the like, which are harmful to either one’s body or possessions. However, care must be taken to not make the animal suffer and minimize its pain as much as possible.

Likewise, it is permitted to kill an animal when one intends to “benefit” from it, for example by eating its meat or making use of its skin, hair, bones and other body parts. The Hadith quoted earlier regarding the sparrow indicates that it is permitted to kill an animal to gain some benefit (manfa’a) from it. As such, the renowned classical Hanafi Jurist, Imam al-Kasani (Allah have mercy on him), states:

“It is permitted to hunt land and sea animals, both whose meat is Halal and whose meat is not Halal to eat. Hunting Halal animals would be to benefit from eating their meat, whilst hunting Haram animals would be to benefit from their skin, hair and bones; or to protect one’s self from their harm.” (Bada’i al-Sana’i, 5/91)

Is mercy killing of animals allowed?

The question is, does killing a sick animal in order to end its suffering come under the categories of “genuine need” and/or “benefit”? If some other benefit is also intended when killing a sick animal, for example to make use of its skin, then there is no doubt it would be permissible, since killing for a useful purpose is allowed regardless of whether the animal is sick or otherwise.

However, if no benefit is intended other than putting the animal to sleep to end its agony, then there is a difference of opinion between classical jurists (fuqaha) on whether it can be killed. Some Schools do not allow its killing, for it is a living soul and thus should be allowed to die its natural death. However, according to the Hanafi and Maliki Schools of Islamic law, if the animal is in extreme pain and close to death and there is no hope of its recovery, then there is no sin in having it killed.

Imam Haskafi (Allah have mercy on him) from the Hanafi School states:

“It is permitted to slaughter a cat or dog for a benefit. And it is better to slaughter a dog if it is close to death.” Imam Ibn Abidin comments, “… for in slaughtering the dog, one is relieving it from pain. Tahtawi said that this ruling is not restricted to a dog.” (Radd al-Muhtar ala ’l-Durr al-Mukhtar 6/474, Kitab al-Sayd)

It is stated in Al-Fatawa al-Hindiyya:

“If a donkey becomes ill such that one is unable to benefit from it, then there is nothing wrong with slaughtering it to end its suffering.” (Al-Fatawa al-Hindiyya 5/361)

In the Maliki School, Imam al-Dardir (Allah have mercy on him) states in his commentary of Mukhtasar al-Khalil:

“It is permitted to slaughter a donkey or mule if one loses hope in its recovery [due to its illness], rather it is recommended to end its suffering.” (Sharh Mukhtasar al-Khalil with Hashiyat Dasuqi 2/108)

So, in conclusion, killing an animal without a reason is unlawful and sinful, but permitted due to need or to gain benefit. This “need” includes an animal becoming severely sick such that there remains no hope in it recovering, and as such, it would be permitted to have it killed to end its suffering and pain, Insha Allah. However, it is better, if possible, to also intend benefitting from the animal in some other way like eating its meat (if the animal is of those whose meat is Halal) or making use of its skin, hair and bones.

And Allah knows best