I'm sorry to hear that Boris and Sophie are having problems. How old are they? If they're seniors then they may need a more easily digestible food for seniors. How are their stools? The reason I ask is that both Alani & Blaze also have sensitive stomachs and I did catch Alani throwing up a few times. They also had soft/loose stools and some diarrhea when they were much younger.

I just recently changed their diet to one higher in fiber and in just one day I noticed a huge difference. They're now on Chicken Soup For The Cat Lover's Soul Adult Light. It has more protein and fewer calories than the regular adult dry and it also has cellulose to help with hairballs. They also make a senior hairball formula that is also high in fiber. Here's the link:http://www.chickensoupforthepetlover...rball_formula/. They also make canned food too. I sure hope that you'll be able to find something that will work for them. Good luck.