Question:
BD”D
Shalom, would animals be allowed to euthanize, like a dog or horse that is suffering and will die, can you sacrifice them so they don’t feel pain?
Answer:
It is permitted to kill an animal that is suffering. To euthanize them is best as it doesn’t cause them any pain, but killing it in a way that isn’t very painful, and will alleviate it’s pain is also permitted. The Chazon Ish was once asked what to do
with a fly that was wounded and suffering, and he said that it should be killed in order to minimize its suffering.
Please see the following post https://dinonline.org/2018/05/31/sick-pet-fish/
Best wishes
Sources:
Dinim v’Hanhagos chazon Ish 2-pg. 40, Noda B’yihuda Y:D 83
