Vent Holes on homemade incubator

[ChickenWendy]

I have read and read through this website but finding a concise answer on the reason for the vent holes is hard. What I want to know is - exactly what are the vent holes for?? Do the chicks as they are hatching need the air?? And if i have a homemade incubator (The Miss Prissy Breadbox Special) and I have 4 - 1/4" vent holes, will that be enough?

 

[rooster-red]

Vent holes are for ventilation of freash air.
Yes, eggs are porus and embryos need fresh air exchange all the way through the incubation process.

 

[ChickenWendy]

thanks roosterred for you answer. Now will mine be enough? or do i need to add more or make mine bigger?

 

[Matt A NC]

The developing chicks need fresh air and then when hatching the actual chicks will need more fresh air.

The large sportsman only have 2 one inch holes.

Matt

 

[rooster-red]

I have 5 holes 1/2" in diameter in my 48 qt cooler bator.

I cover 2 with tape until day 18, then take the tape off.

I have no scientific explanation for how much air is actually needed, I just figured its better to have too many and have to put tape on some rather than not have enough.