Everything you need to know about RERback to summary
Hunting grounds, like any encounter have two menus for them. One for the day and one for the night. Useful if you want hunting grounds only during the day and none during the night
First, you can control with the frequency slider how often you see hunting grounds. It is a ratio of all the frequency sliders from all the encounters, so if you set 5 to one and 50 to another it means the one with 50 has 10 times the chance to appear compared to the 5 one.
Then you can control which creatures you see from hunting grounds These are ratios too, you don't have to calculate the exact % but you simply need to know that 100 is ten times more than 10.
Creatures from hunting grounds stick to one location and try not to move away from it, until you get close enough and the whole group attacks you. This encounter is intended to look like vanilla groups of creatures you often see in the world.