Where to Find and Catch Tepig
From Pokemon Go Wiki
Tepig are found and captured in Nest and Habitat locations.
Nests
Tepig Nests are locations that consistently spawn Tepig.
Habitats
Tepig Habitats are spawn locations where Tepig is likely to be encountered, but not guaranteed the way a Nest is.
Additional Tips and Information
Best Nests
If you know a really good nest or any of the nests above is really good, list them here: