I would also wait a little while before taking any action like tossing them out. I candled some of mine and didn't see any signs of development until around day 8, when I could see definite veining and even some moving embryos in a few. Even still, there were some that I thought for sure weren't developing on day 8 that definitely were by day 10. This is my first time incubating (day 15 today) so I am no expert, but most of my 14 eggs didn't look developed at all on day 6. I can tell you now that 11 of my 14 are definitely developing healthily, so just give them a little more time in the incubator, turning them and monitoring temp/humidity and then see what they're like in a few days. I've read multiple sources that say don't throw undeveloped eggs out until Day 14, just to be extra safe, so you still have quite a few days that it wouldn't hurt to leave them just to see what happens.