While I agree with @bpatters, I don't necessarily follow the advice. I too did a trial experiment with Sherwood pellets and my boys didn't like them. As a healthcare professional, I am very strongly rooted in science and want to see comparative studies for a product upon which such claims are made. Sherwood simply can't produce evidence for the claims they make.
Blue Seal pellets are not generally highly regarded, but they are not the worst either. I originally started feeding them upon recommendation from a couple of respected breeders. I took a break to try the Sherwood and then went back to Blue Seal. There are no perfect pellets, but KMS comes the closest. I have had issues with them in the past and simply don't wish to do business with them again. They are located in the Pacific Northwest and available only online.
Yes, of course, I'm well aware of the nutritional content of Blue Seal but have been feeding them for probably 7 years. My local feed store buys them in bulk and repackages them into smaller bags. Their supply is always fresh and the prices very reasonable.......and my cavies love them. I have never seen any evidence that they have caused problems. If you want to see the published content of BS, you are welcome to PM me, provide an email, and I will be happy to send it to you.