How's likely would this dlc be
Planet zoo Temperate Animal Pack
1. American black bear
2. Rosevelt elk
3. Coyote / Raccoon dog
4. European Hedgehog / Echidna
5. European Rabbit
6. Pine Marten / Otter
7. Mallard duck
Tundra overlaps with Arctic
Taiga (Alpine) most requested animals for this biome are already added
That only leaves Temperate as the last in-game biome without a Dlc
Depends on which way you look at it.
There are 5 packs exclusively or predominatly focusing on temperate animals (NA, Europe, Twilight, Oceania and Eurasia, and Barnyard in a way also i guess).
But if you look for something specificly called Temperate Pack, then no we dont have that. But that could also be said for the tundra, taiga and desert biomes in game.
All that being said i dont think a temperate pack is entirely impossible as there are still a few fitting animals for that theme that people want, the mandarin duck, golden pheasant, black bear and muntjac being the most requested for this. And you probably could pretty easily make a nice pack with these, having a mix of east asian and north american with 1 or 2 for europe and oceania thrown in for good measure.
But the likelyhood imo depends pretty heavily on how many further packs there gonna be.
If there are 1 or 2 more, then id really, really surprised if its anything related to the temperate biome.