Your trying to compare apples with oranges, the only thing these two feed have in common is there chickens feed with out animal proteins and fats. That's it...
Most likely the reason why your seeing less coming out the back end of your birds on this conditioner feed is because it is a high energy low protein feed and your birds are using more of the available nutrients so there is less waste. The Flock Raiser is higher in protein, most likely lower in energy and your birds didn't need as much of the available nutrients to survive and so the extra comes out the back end of your birds as waste.
It has nothing to do with, "fillers" but more so on available nutrition.
Most likely the reason why your seeing less coming out the back end of your birds on this conditioner feed is because it is a high energy low protein feed and your birds are using more of the available nutrients so there is less waste. The Flock Raiser is higher in protein, most likely lower in energy and your birds didn't need as much of the available nutrients to survive and so the extra comes out the back end of your birds as waste.
It has nothing to do with, "fillers" but more so on available nutrition.