Here is the full list of all 20 My Little Farmies achievements.
Build 2 pens for small animals
Place 5 rabbits in pens
Build 32 pens for big animals
Produce 200 goods
Produce 30 different goods
Open 320 boosters
Add 20 building upgrades
Harvest 300,000 plants
Hire 25 assistants
Place 10 animals in pens
Place 70 different decorations on your farm
Expand your farm 9 times
Build 12 small plain stalls
Attained, once you have received a total of 1,000,000 customers.
Breed 20 animals
Produce 320,000 goods made of cereal
Play a total of 250 days
Feed 150,000 animals
Expand 6 pens
Build 20 production buildings