The unusual shape and bright color of yellow crookneck squash make it a standout among summertime vegetables. Like its summer squash counterparts, zucchini and straightneck yellow squash, yellow crookneck is a low-calorie star, with about 24 calories per cup sliced.yellow crookneck squash contains vitamins, potassium and dietary fiber, mostly in the skin which is soft and entirely edible. One cup of sliced yellow crookneck provides 24.5 milligrams of vitamin C, of the recommended dietary allowances of 75 milligrams for females and 90 milligrams for males,The wide variety of shapes of summer squash (Cucurbita pepo) includes squash with a crooked neck, which is also called crookneck squash. This type of summer squash is replanted each year, and it does best grown as an annual in U.S. Department of Agriculture plant hardiness zones 3 through 11 to allow for the frost-free growing season.