You should cook the chicken first.
If it were me, I'd hold out on the bribery foods for a little while longer. A lot of times, once turtles get junk foods like krill and chicken, they'll only want those foods and it can be very difficult to wean them.
How long has it been since you've had your turtle? Is your water temp around 78F?
Water temp is crucial to encouraging eating in cold blooded animals since their bodies regulate themselves based off the environmental temps.
