msarkie I am so sad to hear of your kitty being ill

I see Koala gave you the link to our pet forum...here itis again....many caring helpful members there http://neurotalk.psychcentral.com/forum62.html

I also wanted to mention a catfood mix that saved our Shadow's life..... it is recommended as therapeutic by many vets and where Shadow would throw up most anything we fed him, and used to have severe seizures, now he is doing great.
Initially I was sceptical and not sure about adding the raw food, but honestly it has been miraculous! We had been warned by the vet that Shadow would likely die soon and he is now a robust healthy cat, ever since the food change!

Not sure if small amounts of this would help your precious Picabo.

I use chicken breasts that my meat market single grind for me and use 1/4 cup of the powder mix to 2 lbs chicken as that is what my vet recommended (the company suggests 1/2 cup per 2LB)
The mix may seem pricy at $49 a bag (the also do smaller $12 bags so you could get some and do a trial run) but it lasts long and I calculated it to be much cheaper than the regular petfood purchase over the same period

the THERAPEUTIC mix for sick animals is the Instincts PLUS one (in the gold bag) *not* the InstinctsTC one (in the black bag)

http://felineinstincts.ca/

they also have an article on kidney disease feeding
http://felineinstincts.ca/?p=1505

praying for you and your kitty