I really hope your darling is better. Thank you for starting this thread because we all learn from the experience of others. When Rufus was a puppy, under 6 months, his mother was really ill with pancreatitis. Her owner warned all the people who had pups from the litter, so I have known about the fat issue, and have trained all the family. I always try to avoid fatty food, and cut visible fat off meat. I wanted to point out that other than lean breast meat, chicken does have a fair amount of fat, especially under the skin and around the under carcass so I watch for this. We were given tell tale signs to watch for by her vet, such as discomfort when moving and a kind of arched back. There are two other cockers round he who have had it badly, but both have recovered, thank goodness.
