Barneyowl I would read this first b4 you do anything with Lorenzo..... I had a chicken sit for 3 and a half weeks on 10 eggs. Nothing hatched, all dudd eggs, so I took her off. I thought nooooo Elvis(my cockerel) is infertile. While that was going on I was leaving eggs in another nest to encourage another to clock/cluck/brood for me, and the one I took off started again the following day. After getting advice from Alan42 I left her to sit again.She sat for over 3 and a half weeks on 10 eggs and she got 5 chicks. While that was going on I had another started when the first one first started and she hatched 6 out of 6, but really late 4 or 5 days over. So this year all of mine, and another lad I know who had 2 hens sitting, their chicks came 4 - 5 days late. Anyway I had another start brooding and let her sit on roughly 10 eggs and nothing. There were 2 dead chicks inside of them, the rest stinky watery stuff. But the 2 that died I heard cheeping the day b4 but never made it, and they cheeped 4 or 5 days late. I do not know why this happened, maybe improper storage of eggs to be used, carelessness handling them etc. or even it being too cold or hot under the hen. I would not say that it is definatley your Cockerals fault, I thought the same about mine, but when I tried again I got a result. I also had eggs in an incubator, 14 the first time and I got 1 chick, its a hen wehey. I tried again right away this time with 7 eggs and I got 2 but one had bad foot and had to be put down. The one that survived had a crack in its egg from my 2 yr old daughter from week 2 and its always been fine, that one is also a hen. Good luck if you ever try this again, but plz give Lorenzo another chance......