This is the sign on Chick fil-A in Chinatown in Washington, DC.
My guess for 可 福 (ke fu) is just that it's approximately phonetic to two sounds in "Chik-Fil-A" and has a pleasant meaning ("can be a blessing(?)").
堡 (bǎo) seems to be a suffix in "hamburger", so refers to "chicken sandwich" somehow? But 達 (dá) in 達 堡?