Adding some variation to animal sizes might be a fun way to spice up the difficulty spectrum of hunting.
We currently have a wide variety of difficulties and different animals, but what if there was variation within each individual species? Or even just some?
We have gender variations for some birds, but what about other animals?
Reindeer, Deer and Moose could have female variants that don't drop antlers.
Boar could have female variant with tiny tusks or none at all.
Another idea is to have younger variants of animals too.
We could have young moose calves, young deer fawns, young bear cubs.
Maybe occasionally a female will have a few younglings spawn with her, and maybe the female will agro when any one of the younglings is agrod.
Maybe occasionally entire families will spawn together, with varying amounts of younglings, all agroing as a group like wolves.
Maybe occasionally only cubs and pups and younglings spawn on their own without a parent nearby to give noobish hunters an opportunity to get small amounts of the meat and patches of the skin of more difficult animals they wouldn't otherwise be able to kill.
There are already varying ages of domestic animals, it would make sense to have them spawn in the wild like this too. It would also make sense that the animals that we actually tame and domesticate should actually be the young variants.
ALSO, it would be cool to have the occasional adult animal spawn as an extra large and extra aggressive and harder to kill alpha variant. Maybe these animals have more hp, hit harder and have more meat and a chance of dropping some rare curio akin to a dark heart or something.
Bigger animals can be slower and hit harder, smaller animals can be faster but easier to kill.