Short answer
Yes, plain cooked butternut squash is generally safe for dogs with kidney disease. It's gentle on the stomach and can be a suitable low-fat treat. Just offer a small amount to start, ensure it has no added salt, butter, or spices. Watch for any digestive upset, and check with your own vet to confirm it fits your dog's specific dietary plan.
Butternut squash — Food safety facts
Safe to share · Dogs · full breakdown on the linked food page
Cooked and plain is safe, and gentle on the stomach.
The full verdict, portion guidance and serving notes are collected on the Butternut squash food facts page.