Just noticed I’ve been alittle slack with posting… but as mentioned last post it is incubation season and if you have been to shop you’ll probably have been told how busy it has been :) As a result of an increase in incubator sales, I find myself giving my humidity talk.. alot! So I will attempt to write my ‘lecture’ on humidity here – please ask questions/comment if I miss something out.
We usually recommend for chook eggs you have around 50-55% humidity for the first 18 days and bump that up to 70-75% for the last 3 days of hatching. Everything you read will have slightly different percentages – how else would you sell soooooo many books on incubation? The exact number doesn’t concern me… as proved with the school chickens, you can still hatch under less than ideal conditions. My father-in-law told me when I started at the shop – if you know what you are doing, you can hatch chook eggs in a fry pan – it’s just abit easier in an incubator :) Mother hens do not have hydrometers! In most incubators this means that to start with you fill up a water dish – the manufacturer has done all the calculations for you and then for the last 3 days you fill up the second water dish -or in IM machines, close the vents down to one third.
Humidity is all about surface area of water – it doesn’t matter if the water dish is 5 mm deep or 10 inches deep. If you measuring humidity and want to decrease it, decrease the surface area – cling wrap or foil works well, naturally then to increase humidity increase surface area – sponges are a great way to do this. Other suggestions include using containers like ice cubes trays which allow you more precisely control the surface area of water.
In normal circumstances you will need to check and top up the water about every second or third day. If you find yourself constantly filling up the water dish, consider putting a dish of water outside the incubator to boost the humidity of the air going into it – if the air going in is very dry it will use more water. It also goes without saying that the water you use to top up your incubator should be ‘blood temp’ – just like a babies bath, so the incubator doesn’t have to warm it up.
While they are not necessary, if you do want to monitor the humidity/temperature in your incubator(s) this set allows you to monitor up to three incubators: http://www.wapoultryequipment.net.au/products/thermometer-wireless-thermometerhygrometer-with-3-sensors