Chicken sandwiches, nuggets, salads, breakfast, and sides guidance based on reviewed public sources for United States.
If you're considering the standard Chick-fil-A Chicken Sandwich with an egg allergy, changing the sauce or bun doesn't remove the egg listed in the breaded filet. The sandwich identifies egg, and pasteurized egg appears in the chicken ingredients, so you'll still need to include the filet in your review.
If you're considering the standard Chick-fil-A Chicken Sandwich with a milk allergy, removing the cheese doesn't remove the milk listed in the breaded filet. The chicken ingredients name nonfat dry milk, and the allergen panel identifies milk, so you'll need to review the chicken as well as the toppings.
If you're considering Chick-fil-A with a peanut allergy, the chain's use of fully refined, heat-processed peanut oil is an important detail to review. Chick-fil-A says refining removes the peanut proteins and notes that the FDA does not classify highly refined peanut oil as a major allergen. That distinction may matter to your personal plan, but it doesn't answer every shared-preparation question.
If you're checking the standard Chick-fil-A Chicken Sandwich for sesame, don't rely on whether you can see seeds. The bun ingredients list sesame flour, and the sandwich identifies sesame. A bun-free order removes that listed bun, but you'll still want to ask how staff assemble it.
If you're reviewing Chick-fil-A for a soy allergy, you'll need to distinguish formal soy allergen statements from highly refined soybean oil. The standard Chicken Sandwich identifies soy, with soybean oil in the chicken and bun and soy lecithin in the bun. Chick-fil-A says the Waffle Fries recipe has no major allergen while also identifying highly refined soybean oil.
If you're considering the standard Chick-fil-A Chicken Sandwich with a wheat allergy, changing the bun doesn't remove the wheat listed in the breaded filet. Both the chicken and the bun contain wheat, so you'll still need to include the filet in your review with a gluten-free bun or lettuce wrap.