Wanting to raise chicks from eggs?

hello! im 14 and have always wanted yo purchase fertile chicken eggs to raise. my sister goes to farm camp and she once brought back two eggs. we krpt them on a hesting pad for a while, but they never hatched. i cracked them open and there wasnt even anything inside! haha, so im looking for a site to purchase fertile eggs. i also need to know if a heating pad will be hot enough for them as for ibcubation. i dont want yo spend too much on an incubator, but i dont have supplies to make my own. i do have a large backyard do they can toam freely if theyd like, and ill most likely purchase a small coop large enough for them, or build one myself. do you have any experience raising chicks from eggs? please help me! oh and one more thing! how to i persuade my parents to let me do this??