There you go again. Taking an exception and trying to make it the rule. Certainly there are examples of some slaves being murdered, but such was not the rule. That wouldn't be good business.
Wrong again!
"The death of a large owner is the occasion usually of many families being broken up. Bankruptcy is another cause of separation, and the hard-heartedness of a majority of slaveholders another and a more fruitful cause than either or all the rest. Generally there is but little more scruple about separating families than there is with a man who keeps sheep in selling off the lambs in the fall. On one plantation where I lived, there was an old slave named Paris. He was from fifty to sixty years old, and a very honest and apparently a pious slave. A slave-trader came along one day, gathering hands for the South. The old master ordered the waiter or coachman to take Paris into the back room, pluck out all his grey hairs, rub his face with a greasy towel, and then had him brought forward and sold for a young man. His wife consented to go with him, upon a promise from the trader that they should be sold together, with their youngest child which she carried in her arms. They left two behind them, who were only from four to six or eight years of age. The speculator collected his drove, started for the market, and before he left the State he sold that infant child to pay one of his tavern bills, and took the balance in cash. This was the news which came back to us, and was never disputed.
I saw one slave mother, named Lucy, with seven children, put up by an administrator for sale. At first the mother and three small children were put up together. The purchasers objected: one says, I want the woman and the babe, but not the other children; another says, I want that little girl; and another, I want the boy. Well, says the Administrator, I must let you have them to the best advantage. So the children were taken away ; the mother and infant were first sold, then child after child - the mother looking on in perfect agony; and as one child after another came down from the auction block, they would run, and cling weeping to her clothes. The poor mother stood, till nature gave way; she fainted and fell, with her child in her arms. When she came to, she moaned woefully, and prayed that she might die, to be relieved from her sufferings."
http://www.spartacus.schoolnet.co.uk/USASclark.htm
Walt