No, of course they aren't. If 500kg+ wants to kill something then it will do so. We do however have an exceptional database with many, many repeat customers and happy people that LOVE their GutzBusta's! Do hay nets work for ALL horses. No, they don't. Does any horse product work for ALL horses? Some horses (thankfully not too many) will not accept a hay net, some can 'learn' to destroy nets, or you may have to play around with hole sizes until your horse is happy to eat from the net.