ramp length for pop door?

[LittleClucker]

My pop door is 2 ft off the ground....how long should my ramp be in order to have my chickens not be skittish of it? Or what degree of slope should i not exceed? Thanks.

 

[HandsomeRyan]

My pop door is about 2.5' off the ground and I have a 6' ramp leading up to it. I also put treads on the ramp spaced every 3.5" for the entire length of it to help the little birdie feet get traction. The girls do just fine on it. You can sort of see it here:

 

[locoguru]

By door is 12" off the ground and have a 3' ramp.

 

[LittleClucker]

Thanks guys that helps me get a ballpark idea of what to do