So, now comes the hard part - time for that sit down with your kids where you go over the importance of being good stewards to the animals who are entrusted into our care. This isn't about blaming your son or making him feel badly, it is about taking an unfortunate situation and making it a life lesson that will, hopefully, help him to move forward with a better grasp of the gravity of how his actions can have a direct impact on the lives of others and why it is SO important that we do what we say we will do/have done, especially when the lives of others are at stake. He didn't mean to kill the bird - he just didn't think about the unintended consequences of the choice he made to shirk his duty. You don't take him off of chicken duty - you keep him on it, with this being his job EVERY day- those birds eat and drink before he does - and you go along behind him EVERY day and verify that it has been done and, if he hasn't done so at the times he knows he is supposed to he goes right out there and does that chore as well as a few more (or other consequences as per your parenting style). While we have not had a loss of life result, I have caught my kids (when they were younger) not necessarily doing what they were supposed to have done. Leaving an animal without food or water in our home is a cardinal sin........