No. You don't need to add salt when cooking chicken breast for cats. First, cats cannot absorb seasonings, and second, cats don't sweat, so they lose very little salt. Furthermore, cats' kidneys and urinary tract systems are relatively delicate. If cats eat salty food, it may cause indigestion, increase their risk of urinary stones, and lead to hair loss. 
How long should I cook chicken breast for my cat?
Fifteen to twenty minutes. Don't cook chicken breast until it's undercooked, as this may not kill any bacteria present, potentially causing diarrhea in your cat. Also, don't overcook the chicken breast, as this will cause nutrient loss and make the meat too dry.
