Mountainbeauty
Chirping
- May 31, 2017
- 74
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https://poultrykeeper.com/incubatin...hat-humidity-should-i-use-to-hatch-duck-eggs/
Air Sac Development
The image to the right shows you the ideal air sac size at different stages of incubation in days, if you follow this, you shouldn’t go too far wrong.
If you print it out, it should be close to the actual size for most light and medium breed ducks.
There is another image of a chicken and duck egg at the bottom of our page on candling eggs that might also be useful to you too.
Notes:
Air Sac Development

The image to the right shows you the ideal air sac size at different stages of incubation in days, if you follow this, you shouldn’t go too far wrong.
If you print it out, it should be close to the actual size for most light and medium breed ducks.
There is another image of a chicken and duck egg at the bottom of our page on candling eggs that might also be useful to you too.
Notes:
- Use a soft (e.g. HB) pencil to mark the extent of air sac development on the egg shell and compare it to the egg above.
- If the air sack in your duck eggs is too small, your incubator humidity is too high. If the air sack is too big, your incubator humidity is too low.
- The air sac changes slowly at first. Most of the change occurs from 18 days onwards.
- Weight loss is not proportional to the change in air sac: it will be fairly constant.