I understand that this theoretically falls under the category aditional creatures and this suggestion might be taken down because of it, but I feel that it may be worth a try and still suggest it, given you're not already planning to do something of the sort.

So as the title says.
I'm curious if you will ever, or are planning to at spome point in time to replace the vanilla animals with your model equevalants.
I really like how you model your creatures and I absolutely love the mechanics you have going on.
As such, my suggestion includes a domestication mechanic.

With pigs you could use your wild boars as a basis and disable natural spawning of vanilla pigs. Wild boars would instead eventually begin producing domesticated pigs after several generations of domestic breeding. Arguably the same could be used for cows where they have a wild equevalant at first and eventually start producing a more domestic equevalant after several generations.

Chickens wouldn't really get much of a change aside of a model update and perhaps even something similar in terms of how they breed. Maybe even remove the ability for them to just 'pop' out an egg entity that floats about and instead maybe spawn several 'nests' throughout world generation where wild chickens lay their eggs in and generally stay around said nest.

Sheep would be replaced with a goat equevalant perhaps? There are goat species that have thick fur like the mountain goat. This could be used as a basis to follow the same princible of domestication as the animals mentioned above.

For wolves, that's pretty straightforward. You wouldn't be getting a golden retriever after several generations of domestic breeding of course, but instead a more tame domestic wolf breed that may or may not have some attribute changes as a result of the domestication process.

As with all animals, another feature of the progressive domestication would be their retaliation or a special item.
For animals meant to be used for their meat, one could use a special knife that allows a player to instantly take down an animal that's past a certain generation.
With that I mean, let's say, a 5th generation cow would get instantly downed by the item in question, whereas a 3rd generation cow would not, and a player would instead need to down them like everything else.

Domestic wolves could maybe unlock more commands as they progress through the domestication?
Generation 3 would unlock the ability to sit and follow.
Generation 5 would unlock the ability to defend you in combat.
Generation 6/7 and up would let the player direct the domestic wolf what to attack and maybe even some other tricks.

What do you think?

I'd love this!
Vanilla animals are super derpy and I'd love an overhaul.