This is a bit about it I found.
"It is a surprising fact that, although eggs must have very stable temperatures to incubate successfully, periodic cooling can be a good thing and far from harming the development of chicks, can actually lead to more successful hatching.
Bird breeders have known for many decades that eggs can be cooled for limited periods of time during incubation without causing problems but recent research has shown that hatch rates can actually increase significantly as a result of cooling.
Follow the link to read the full research paper on cooling eggs during incubation.
Cooling is an entirely natural process as most birds will get off the nest at least once a day and leave the eggs unheated for a significant time. From Brinsea’s 40 year experience, the best hatch rates are always achieved when the incubator can best mimic the natural nest conditions. For this reason Brinsea® have incorporated a cooling option in our Advance models of egg incubators for 2012.
Based on the results of the research paper above the user of an Ovation 28 Advance could expect one additional egg to hatch on average.
Brinsea's cooling feature turns the incubator’s heater and low temperature alarm off for a select period but keeps the fan running. After the cooling period is complete the incubator reverts to normal temperature and the alarm is automatically reset. The cooling function is optional and the user can select cooling periods of 60, 120, 180, 240, 300 and 360 minutes with fixed 24 hour intervals. The default setting is that cooling is set to off. This new function applies to the Advance and Advance EX versions of the Mini II, Maxi II, Ovation 28, Ovation 56, Ova-Easy 100, 190, 380 and 580 incubators. The cooling feature can also be found on the older Brinsea models of the Advance and EX versions of the Mini, Octagon® 20, Octagon® 40, Ova-Easy 190, 380 and 580 models"
https://www.brinsea.com/articles/news/cooling.aspxJust wanted to know if anyone knew if 30 mins cooling was too much ? and if there was anything i could do to help the eggs if it was