As of version 2+, this mod will be rebranded from Winter Pigs, to Better Pigs. I've chosen to do this to avoid having to create a new mod for these new features, if all you want is your pigs to go out in winter, then it's very easy to disable the new options in the config, or via gmcm.

Changes a few key things about Pig behavior:
1. They can now eat golden animal crackers, pigs which have eaten these will get an increased chance to find truffles
2. The game has a default limit on the truffles a pig can find (~1-2 on average), this can now be disabled
3. When pigs do their truffle dig up animation and the farmer comes to pet them, that animation is cancelled and no truffle will be found. To avoid this there's an option to not allow petting while this animation is happening.
4. On top of the previous 'Pigs can go outside during rain and winter', they (along with all other animals) can now be configured to go outside during more weather types categorized as follows:

Horrible Weather:
- Lightning
- Snow
- Green Rain

Bad Weather:
- Rain
- Winter

Additionally, there's options to keep an animal indoors regardless of weather or season (Villagers don't need to know I'm re-creating jurrasic park in their backyard)

Values input in these options must be a comma-delimited piece of text with the English type names (e.g. "Pig, Cow, Duck, Chicken, Ostrich"). If you can't find this name, just ask and I'll (try to) find it.

Pairs well with :
Better Truffles

How to install :
1. Install Smapi
2. Unzip the file and place it in the mod folder

[Source Code]