My cat is prone to developing crystals in her bladder, so our vet prescribed Royal Canin S/O food. The problem is that she also has a sensitivity to chicken and therefore either vomits or has diarrhea. I've researched all the Royal Canin products with the S/O complex, and they all seem to contain chicken. Is there another food you can recommend or another way to prevent her from developing crystals in her urine?
Royal Canin makes a diet approved for treating the same conditions as S/O that is primarily used to treat food hypersensitivities (diseases where patients do have gastrointestinal signs due to the food they eat). The food is called Hypoallergenic Hydrolyzed Protein (HP). Many adverse reactions to food are due to protein sensitivities to chicken or beef, so the HP food is a broken-down (digested) soy-based protein. Although it does contain chicken fat, sensitivities to the chicken fat itself would be less likely. It is important to make any diet transition slowly (over 2-3 weeks) to minimize the risk of any gastrointestinal upset. This diet is only available in a dry form, so encouraging water intake is recommended along with the diet to encourage urine dilution. Please check with your veterinarian to see if there are any other contraindications to the diet based on your cat's medical history. In addition, consultation with a board-certified specialist in veterinary nutrition may be beneficial if you can't find a commercially-available diet that works.