If this offers any clarity, on that same rotation we had a couple of cats develop this really weird, really severe anemia that we couldn't find a cause for. Not littermates, but same household since they were kittens. Absolutely no changes in the household except for a change in diet (same brand, different food). Without writing you a novel, just trust me that we worked the case up extremely thoroughly. The cats were hospitalized for a couple weeks, I believe. Ultimately, I ended up calling the food company and asking if they would test the food because we were concerned that it was the cause of whatever was wrong with the cats. They refused to test it and told me that they don't test any open bags of food -- which I can somewhat understand but that meant our only option was to contact the state vet and ask if they could test it. Ultimately, we didn't end up testing it because the owner's mother-in-law (or some kind of relative) admitted to using an estrogen-based cream, even after stating that this scenario wasn't possible, and we assumed she'd been leaving residues on furniture, or petting the cats, and the cats were potentially getting exposed that way. In my brief experience, it seems that pet food companies are pretty unwilling to test their food unless there is some kind of massive issue that warrants a PR response on their part. I'm not sure if anyone has any different experiences on this forum.
