Here's the BYC treats chart. Chickens have different preferences for treats. BOSS is very popular, once they figure out they are good; you may have to offer them in something moist at first.
lol, my chickens do not get cooked for... they get what the toddlers (daycare) leave behind... sometimes that is TOO much! Lately when I don't have much in the way of scraps for them they get baby cereal (cause I have it and no babies to feed it to) mixed with whey from the greek yogurt I have been making.