Chicken plucker diameter

[Sabz]

Hi guys,

I am building a small scale plucker, similar to this:

http://www.millerwelds.com/interests/projects/we-build/home/project/4876720788

In the book that I follow to build it, the cylinder with the plucking finders is 4in diameter.
I have stuff on hand to build one with a 3in diameter.

Would that be too small?
Trying to reuse what I already have rather than buying new..

Thanks!