Correct Anser
Dear Brother,
You have asked a very practical and a very important question, if you feel sin about innocent animals now you have start becoming to search about Dhamma which been preached by Our Lord Buddha.
if you are a Englishman you have to find a professional translator and get translate Kamma Vipaaka e book which I have posted on one of my previous posts then you will get a much better idea.
before I answer your question I have to clear your FAQs,
What is Wild World? (Its not the wild world which you watch on Discovery)
From the smallest animals that cannot been seen by eye to the biggest animals with large body scale all been en-counted as Wild world. they don't have their own safe places they always live with fear and aggressively they eat their own kind too.
Why some ones sole been stuck in a animal body?
According to preachings of Lord Buddha Kamma is the relation for all animals. what your thoughts that is your Kamma, good kamma brings you
happy and good life beings in future borns, bad kaama brings you unhappy life's like poor animals. even a human who have done lot of good things in his life can become a animal as if he get a bad thought that he have done in his life time before few seconds he died, then according to that though his sole moves in to a scalling, Hell,
Life is like a coconut oil lamp which been kept in a middle of a huge ground, it can be blowed off by the wind wich been blowed from all directions or by an animal. till you have enough good kamma done in previous life time decided your this life time. and what you do today will be decided your next life time. because of bad things human, god or what ever the species does if kamma been decided to transfer him in to a animal, he ll become an animal.
answer for your question,
once the Bad Kamma been finalized (Finalization period is seriously a huge time
its one of the most most most most most most rarest thing in the world (once Lord Buddha Preached to one of our Greatest Buddhist Monks that a very small sand on loard buddhas sacred finger is equal to the chance you have to become/ born as a human and rest of the sand in the whole while world is your chance to become as an animal in the hell.
your good Kamma want work until you become a Human or a god in the heaven.
one life time in the smallest hell is 900,000 x 30 x 12 x 500
there are so many things to learn my friend so you have to get translate some good buddhist books been published by "Most Ven. Renukane Chandrawimala Tero"
If you really afraid you have to find about dhamma like a person who getting burning his head.
So call me if you want to know more about your question,
0777 983 807