Use of side Force Pens takes advantage of the width in larger sheds. With a large initial load up capacity, this style suits a smaller number of stands and a smaller workforce.
An optional release gate can also be included at the back of the Catch Pen to feed sheep back into the Holding Pens.
Front Fill Races use the placement of a decoy sheep at the top of the race to draw sheep up from the Fill Pen. This style of pen requires Sheeted Fences to be used so that the line of sight for the sheep is always forward. This allows for a continual flow of sheep into the Catch Pen when loading up.
Pens with Front Fill Races do require more overall width than Back Fill Pens.