if you wanted to you could end up with the same bird... with this they used a tailed and tuff less Araucana so it might as well have been a cull for that breed... but also both the muffs and the tailless gene are incomplete dominant so if a bird has them it will show them... so by using a tailed and tuff less bird they new those genes where not present so it was simple... if u use Ameraucana u will have to contend with the beard and muffs... and they can hide and not visually show even if a bird has a gene for them... so if you where breeding for a beard and muff less bird (like the UofA birds) u would have allot of culls that showed up with beard and muffs for several generations... of course if you just wanted an egg layer and did not care about beard and muffs it would be no problem at all...
The gene for beard and muffs is a simple dominant gene. Easy to eliminate, if the bird is clean faced it is not 'hiding' anything and bred to another clean faced will breed true. The tuft gene, like in the Araucana, is incomplete in its expression.