working dogs tend toward more variation than show dogs. for example Blackmouth curs & catahoulas from working lines (unfortunately there are such things as show only lines now) can range from 40-90# 20-26". the same for american foxhounds, many of the coonhounds, coldblood greys and staghounds (even more size variation than this in fact). on top of that working leopard dogs have heads ranging from slight wedge to rectangular to heavy square heads (like a standard AB or english lab). the variation comes from breeding best worker to best worker w/o regard for looks.