food doesnt really matter mate its all about trust and routine
if the bird doesnt trust you you have problems
start letting them out at dusk cos natuarly the pigeon will come to roost at dust and over a period of lets say a wk draw in the hours of lettingg them out
i can let my birds out fed or unfed and they will trap almost straight away but what ever doesnt trap do not reward and feed just shut the door it will soon learn the system in and fed out and hungry
hope this helps