The seeming simplicity of chicken salad fools many a cook. Yes, it is just chicken, mayonnaise, maybe some diced celery and onion. What could possibly go wrong? To a true chicken-salad connoisseur, the devil is in the details. Is the chicken all white meat with no gristle? Is the mayonnaise of the highest quality? Are the celery and onion fresh and sized to complement rather than overwhelm the texture? Are the seasonings tasty but subtle enough to keep the spotlight on the bird? At the Woman's Industrial Exchange, the answer to all of these questions is an unqualified "yes." Plus, the Exchange offers its chicken salad on an overstuffed sandwich or at the heart of its famous tomato-aspic and hard-boiled-egg platters.