I have about 20 BCM eggs incubating. They are on day 16. I've candled them and removed the clear ones, however I'm wondering about any others that may not be viable. Could they explode? Since the shells are so dark, I'm not sure what is in them if it's not moving .I saw definite movement in 4 or 5, but I didn't want to leave the lid off too long to watch for movement in others. How important is it to determine viability? Can I just leave the questionable ones in there?