I bought 3 dozen (36) "fertile" eggs at Trader Joe's two weeks in a row. The first batch I got in Burbank, California. They were about 6 days old and by the time I put them into the incubator I think they were maybe 9 days old. ZERO development...maybe one wasn't completely clear so might have at least started to develop. The second week the eggs were from Los Angeles. Those eggs were only 3 days old and I got them into the incubator when they were about a week old. I just candled them and 17 of the 36 look great with a lot of distinct veins and embryos moving around. A few more haf blood rings or at least looked murky as if they had started to develop. I know that they might have had completely different handling or even refrigeration temperature but I'm thinking that from here on out I'll only try them when I find them about 3 days old. I'll be curious to see how many hatch and how well they hatch.