Death

So death is part of life... but how do you explain that to three little kids who have lost 4 loved pets in the last two weeks? About two weeks ago I accidently killed our chinchilla that we have had since Sarah was about 2. Later that week, Josephs guinea pig got sick, and died. Well, unknown to us guinea pigs don't want to live "alone" after their littermate dies so they just starve themselves to death. Hannahs pig died three days later from loneliness... Well the kids were just so sad that their love was not enough for this little pig and that she would do that. It has been another week, and Sarahs pig died from loneliness today. How do you explain to them that it was not something that was their fault or a punishment from Heavenly Father (which is the new idea) and that death is just part of the deal? Anyway, just throwing it out there for thought...