For 24 hours, The Mystery Stables can be purchased for just 15 BB, at the Supply Store

You place it on a 2x2 empty square, and wait 5 hours

After 5 hours, click on your mystery stable,
you will receive
400 EP
and your mystery stable will change into either:

- a Classic Stable I or Yellow Upgrade (up to your actual level)
- a Classic Stable II or Orange Upgrade (up to your actual level)
- a Production Farm (up to your actual level)

or could even change into
New Stables, Rare Stables:

- RARE -
- Moose Reserve

- RARE -
- Kangaroo Shed

- RARE -
- Bat Roost

- RARE -
- Reindeer Stable

- RARE -
- a "birthday edition sheep pen"

The Birthday Sheep Stable
gives 2 sheep, and 75 EP every 10 hours with sheep feed,
or 8 hours with water.

- NEW -
Butterfly House

Gives; 70 EP
Requires: 1 butterfly feed (10 sunflowers)
time 12h
with water 9h36
power-food 6h
power-food + water 4h48

- NEW -
Squirrel Hut

Gives: 80 EP
Requires: 1 Squirrel Feed (1 walnut, 1 apple)
time 14h
water 11h12
super food 7h
super food + water 5h36

- - - - -

here is an example of how the "change" happens:

You might need to refresh (F5) to see the new stable.