The ones I found just said FERTILE if they don't say fertile they are likely to explode in the incubator, but as long as you candle them and toss the ones that aren't growing you should do fine. here is a link to show you how to candle...
I did the same expirement in 6th grade! I got my fertile eggs from trader joes and all 4 hatched! You might want to try TJ's but if they don't have it I don't know, I had the same problem when i went to get my eggs and no other store had it but TJ's. Hope you find some!