 This line — with many non @-@ hamburger sandwiches , including chicken and fish — significantly expanded the breadth of the Burger King menu . The amount of new additions , several new sandwiches made with disparate ingredients was made possible due the design of Burger King 's kitchen . The chain 's kitchen is modeled around a more flexible concept that allows for a multiple work @-@ flow operations where preparation stations can be re @-@ tasked more easily . In comparison , McDonald 's kitchen at the time was a more rigidly designed assembly line concept intended to quickly produce a more uniform product and was not easily adapted to new products . This more rigid system prevented McDonald 's from broadening its menu to effectively competing with Burger King and other similar chains that were more flexible and were better positioned to expand their menu . 
