I was going to put 34 eggs in my incubator today (Wed.), but in order to avoid a staggered hatch, I am thinking of waiting until Monday. The oldest eggs stored in my basement will be 12 or 13 days old then. Are they too old to be viable? I could collect more eggs from my chickens Friday and this weekend if you all think that the 12 or 13 day old eggs won't be much good. Those eggs will be just wasted and the work of properly cleaning and collecting and storing them will be all for nothing. Maybe I'll just try them and keep a record of which ones are which so that I'll know for later hatches.