This is Chirpie,he will be 3 this coming July 4th. He was raised on 18% starter and never had anything with a higher protein. At about 6 months I start to supplement with dry cat food. He s a big healthy boy who has never had any health issues. I have to be doubtful that it was the protein level that caused you to lose them.
Did you ever give vitamin and electrolyte supplements? What protein were the parents on?