Ok so I have done this before with much success. Recently I moved back to the country and of course jumpped right in. I had some old styrophome coolers for transporting fish when we moved. I cleaned them out and decided to use them for incubators. (Last time I used clear plastic tubs with covers) I have pine shavings in the bottom and initially i used one bulb as always before but the hatch was not so good. out of 50 eggs (countin the 6 duds and a few that just stopped growing early on I ended up with 12 chicks. last one hatched with a protruding navel and looked seemingly normal by the time it was 4 days old. after being transferred to the brooder with the rest I found just two hours later that the others had killed him. They really did a number on the poor lil one sadly. Then I lost another I think because we hit a cold snap and he got too crowded. Anywho... not an over all good hatch. My temps were irratic after I put the eggs in. I could NOT keep them stable. They seemed to rise more overnight then during the day. Woke up one morning ant temps were at 104 at mid egg level. That happened three or 4 times so I know the problem as to why the hatch was bad. My problem was getting temps to stablize so I could start my duck eggs. I changed the set up. First the electronic thermometer/humidity reader showed to be about 2 degrees off. Humidity levels would adjust instantly if I opened it for turning but the temp never seemed to budge for a while and when did it would only fluctuate by 2 degrees at a time. I now use the electronic one to tell me room temp because it was just getting too warm inside the bator. I have as you see a total of 5 bulbs. the largest being a 15 watt and the others are 4 watt night light bulbs. I evenly distributed heat and lowered from a single 45 watt to smaller spread out ones. slightly less heat then the one 45 but it has made a world of difference. My room temp MUST stay between 64 and a max 70 degrees for the bator to maintain a spot on 100 degrees. This I have achieved. My house is set at 66 which makes us comfortable andkeeps the bator stable. I am in the process of building a much larger one with different materials, thermostat, fans and heating rope rather than bulbs. But in the mean time i am so far so good. Yes I know there is no water. I have always misted my eggs until the 20th day then we add a water bin with sponge. I have always had a good hatch this way. . My Pekin hen has layed 20 eggs so far. The first one she dropped by the pool and one of the boys pecked it open. The 19 after well you see 17 here. one was pulled yesterday at 11 days. I have two set aside from yesterday and today. I only hold them for 6 days then incubate so there are different sets in here all marked. I have a hatcher set up much the same way for when the time comes. And I always set them 4 to 6 days apart to allow my hatcher to remain closed until finished. I candled all my eggs yesterday and all but the one are right where they should be development wise. My question is... why do I have so much trouble with a single bulb in styro as opposed to plastic? Does anyone have any suggestions on how I can improve the overall stability in the baitors?