Hi, thank you. We are so stuck that any advise is great. We are from NZ and don't have an issue with Genetically-Modified food, although I'm not so naive as to think it's not in our food chain,but most of the meat we eat is home kill, veg and fruit are grown down the road, and because he was born with a kidney condition have always shyed away from prepackaged food. Interestingly though, because of the kidney condition he was on Antibiotics for the first 18months of his life and have often queried that as a possible cause. Thank you again and I will look into the rope worm stuff.