my ducks LOVE to play with string thats hanging off of things. i don't know why, but they are each playing with a string right now. they had one hanging from a tarp inside their pen, but my mom looked out and they and pulled it down far enough that it as a loop and one duck got his neck stuck in it. we were able to free him before any damage was done. but after that, i took the strings out and got some new toys for them. (dog toys, one rope toy and then a turtle) i hung them from the pen, and they haven't touched them. do you have any idea why they love strings so much?