15-25 or more is the usual range of when they lay. good luck! ive had chickens start at 15 weeks and some at 28-30 weeks just depends on the breed, the bird and its nutrition and sometimes even on the pecking order type of thing.... the top hens will be the first to eat (usually) therefore they will get all the good bits and the best nutrition then say, a bird that is low on the pecking order.. i would start putting some golf balls or easter eggs out in the boxes! one thing not to do and ive done this and im shamed of it ahah NEVER put styrofoam eggs in there
they will attack them and eat them lol
best of luck to y'all!!

best of luck to y'all!!