We recently bought a Corti AF50 incubator and have just completed our first cycle of hatching. It was ordered from France because it was more cost effective and it came with a plug suitable for Bulgaria. It is a huge flipping thing, but it takes up to 49 hen's eggs in 7 rows of 7 separated by removable plastic fence thingys, and to be fair there did not seem to be any wasted space.
There is a motor that automatically turns the eggs, hence two plugs, one for the motor and one for the incubator. We also bought an egg candling torch and a hygrometer. A thermometer was included in the incubator cost, which was graded between 35.8 and 39.7 deg C. There are two water reservoirs in the incubator and to start with, we filled one then later when the humidity needed increasing filled them both. They needed topping up every day or second day. When one reservoir was used, the humidity stayed about 45% and increased to around 65% when the second reservoir was also filled on day 18 of the incubation period. Also, there was a temperature adjustment screw just above the lid allowing easy temperature adjustement
At the start of the incubation (of 21 eggs collected over 3 days), we had difficulty in regulating the temperature because even after turning the adjustment screw, the temperature was always indicating too cold. We put in a household thermometer and it suggested the temperature was too hot so we bought a medical thermometer and by good luck rather than good judgement found the temperature was about right.
On day 15 we candled the eggs and decided to scrap 6 of them which were not developing. On day 18 we removed the turning motor, filled the second reservoir and removed the plastic fence thingys then added covers to stop the chicks falling into the reservoirs below. On day 19, the first chick hatched and overnight most of the rest hatched too. 3 of the 15 remaining eggs did nothing, one chick tried to hatch and died with its beak sticking out of the shell and we helped 2 chicks struggling to hatch, but they subsequently died a couple of days later, so in the end we have 9 chicks from the 21 eggs incubated, and are in our brooder awaiting introduction to our hens in a few weeks.
While the incubator was easy to use generally, I think at the start we had problems achieving a correct temperature and it looks like we may have been supplied with a rubbish thermometer, and in hindsight we probably should have callibrated the suppled thermometer against a medical thermometer to make sure everything was going to be ok. This may have affected the number of eggs that hatched, and it makes me wonder just how accurate the hygrometer might be.
Anyway, I hope this review and observation is of interest and assists anybody thinking of bying/using an incubator. Please feel free to add your own incubator reviews below! Having gone through this exercise, I do have some questions which will be posted in due course. Finally, any suggestions as to how we might improve the hatch rate would be appreciated.