Empty space

[ga_goat]

Have less than 3 doz eggs to set , and incubator holde 120 should I fill bottom tray with waterbottles to keep from having so much empty space in the box .

 

[Ridgerunner]

It won't hurt. The more thermal mass you have in there, the more stable the incubator will be if you lose power or have a temporary spike. Water bottles are great at storing that heat.