The subject of this thread I have lived with during my working life as a mink-farmer.
Given nature is occupied with numerous creatures that survive living on other creatures it is absurd to think they all once lived on plant life before the Fall and after it 'evolved' the means to live off living creatures. The design of many creatures is 100% carnivore, be they ant eaters, insect eating swallows and swifts, many kinds of plankton eaters etc. and of course polar bears.
as a child I used to think death in the wild was cruel, yet for the survival of creatures on Earth it was necessary. And that is why God said his creation of such creatures was 'good.'
As an animal, bird and fish lover, I found these qualities were necessary to be a mink-farmer. To produce a good pelt you had to treat your animals with good lodgings, food and water, every day of their lives.
The actual killing of the animals was of great concern to animal lovers. I have debated the keeping and killing of mink many times, even once at a university. The hall was filled with females who were anti mink farms, but upon a vote at the end I won the debate.
My encounters with animal-rights groups, as distinct from animal-welfare organisations, was most interesting, some points I will discuss here. In debates with them I found most are non-Catholics who believe humans evolved so have no more rights than animals. When Walt Disney gave a human character to Mickey Mouse animal-rights began. Then I found out many were vegans. In debates with these I pointed out to them that veganism, portrayed as saving animals, does more harm to animals than those who eat them. I then go into my litany of harm they cause, forests with its wildlife cut down to grow veg. Insecticides that killl billions of bees, butterflies and other insects. Finally I ask who perpetrated the greatest cruelty to animals in history? It was a disease used to kill rabbits who were eating the veggies' carrots etc.. myxomatosis. Rabbits would go blind and starve to death over a period of up to three weeks. CRUELTY PERSONIFIED.
So, having proved that eating veg is not cruelty free on to mink farming.
My reply was that my right to farm and kill mink came from God. That said, my same religion forbids human cruelty towards animals. They counter by saying caged mink is cruel and killing them is a cruel exercise.
Throughout the ages animals are 'housed' as is appropriate for the different kinds. Mink are caged to keep them clean and healthy. They a vicious animal and apart from mother and kits up to 6 weeks, they have to be kept apart lest they kill one another.
There are different ways of killing mink, gas, injection of manually. For me, gas and injection took handling time, prolonging the exercise. I could catch and kill a mink in 5 seconds. Before it was aware of what was happening it was gone, no stress, no cruelty.
Finally, my Catholic opinion of the death of animals. Since Mickey Mouse was given a human identity, most people think that animals think like humans and are as aware of the past, present and future as we are. They believe animals interpret pain as humans do, are aware of it as humans are. If this were so, God's creation would make Him the cruelest of all, creating lions that kill by a slow horrific death. I do not believe this. I believe an animal has no idea of death, no awareness. An animal can obviously feel pain, but does not understand pain like a human being understands it. The two, an animal and a human are worlds apart in there ability to REASON. They are confined to their nature. A lion does not consider itself wrong when tearing an antelope apart, an antelope does not comprehend its being torn apart. Neither have the ability to think outside their nature.