Would you care to provide some - any - evidence (a properly written and refereed published paper, not marketing blurb or any individual's opinion) for this so-called rule that anything up to 10% is OK?The general rule of thumb is that anything else should amount to no more than 10% of their diet and they will still get a balanced diet. In practical terms, if they can't clean it up in 10 to 20 minutes then it's more than that 10%. You can feed them other things every day if you wish as long as it is below that 10% threshold.