The only way you can know for sure is to candle again in about 3 days, and see if there is any change.I'm not sure if it's because the veins are breaking down or because the shell was thicker (or just wish full thinking)
I've had as many as four thermometers in my incubator at one time, plus the one on the unit. All five registered different temps. So it could be they are just not calibrated correctly (cheap little things), or there are different temp zones. I'm still struggling to get accurate and consistent readings, too. I spent quite some time testing, calibrating, adjusting, insulating, and modifying my newest unit (Incu-View) before introducing eggs to it.I have two extra thermostats in the incubator and one side has consistently been a full degree c less than the other, I got them on day 4 as after 48 hours the display on my unit we awol and was changing temp readings every few seconds and I didn't have another incubator to transfer the eggs.
That's why a LOT of folks here strongly recommend the more reliable brands - Hovabator, Nuture Right 360, Brinsea, a few others. Even the Chinese made Kebonnixs is a great little unit, and not expensive at all. Look for one with good customer service and great reviews. Settle for nothing less.
I haven't heard that, but don't dispute it one way or the other. I know only this, that any GOOD incubator must hold to certain parameters: Air circulated, consistent 99.5-deg-F (37.5-C) temperature throughout, and consistent humidity 30-50% days 1-18 and 70-80% days 19-21. Automatic egg-turning is a plus but you could do it manually, too.I've been told home made incubators are better?
However, once you spend the $$$ to build/buy a cabinet, racks, turners, heater(s), fan(s), temperature and humidity regulators, and sensors - and all the hardware and wiring to put it all together - you'll have spent more money than if you just bought a good incubator from a retailer. Folks who invest the bucks, time and effort to build a homemade unit are usually hatching a great number of eggs at a time - because those retail units are easily $1000-3000 (U.S. dollars).
I don't hear about great hatch rates with a little homemade box, light bulb and thermometer. They're actually pretty lucky if they hatch anything.