We recenly purchased a toy for Chicken our grey, she was playing happily with it when there was a clunk sound, we looked round to find that she had undone the split ring holding the toy to its chain, we though this was a one of event, put the toy back together and rehung it up. Now everytime she plays with it she is able to undo the split ring.
If anyone needs any keys putting onto a key ring we can lend them Chicken.