He's a source of many stories about kindness to animals, and here's another fine story from Albert Schweitzers childhood from when he was 9 years old. This extract (which is his own words) comes from the 1957 TV documentary on Albert Schwitzer. This story has a real childhood innocence about it, but the remarkable thing about it is to think he was only 9 years old when he decided to live by this principle and did so for the rest of his life.
"An experience I had during these years made a lasting impression on me. A neighbour son and I had made sling shots from rubber bands. One Sunday morning he said to me: "Come on, let's squat in the hills and shoot birds". This seemed a horrible idea, but I didn't dare object from fear of being laughed at. The birds were singing sweetly in the morning sunshine so unafraid of us. Crouching like an indian, my friend put a stone in his sling shot and took aim. Obeying his look of command I did the same with acute pain of conscience. At that moment the sound of church bells began to mingle with the sunshine and the birds song. To me... it was a voice from heaven. I frigthened away the birds to protect them from my friends shot and ran home. Ever since, when morning bells ring out in the morning sunshine I gratefully remember those bells for they rang into my heart the commandment: Thou shalt not kill."