What should I watch out for when boiling chicken breast for my cat?

Quick answer

It's a great protein source. When boiling it, don't add any seasoning at all — salt, pepper, garlic — just boil thoroughly in plain water, then shred it into thin strips along the grain. Chicken bones become extremely sharp when cooked and can puncture the esophagus or stomach, so bones must be completely removed and only the meat fed.