Once you level up to a different things like treat farms. Once it has a upgrade sign on it you click on it. :)
you go to the market then click buildings and then click treat farm
The large treat farm unlocks at level 5.
22
If you mean food, you build a treat farm and grow it there.
It costs 25 gems.
Go to your habitat and press UPGRADEYou have to be at a certaint level
12
buy lots of treat houses
You can upgrade your farm by going to the "Market" then click on "Expand Farm" then there you will see choices of expansions. Expansions depends on your level though.
you get another egg slot for hatching it's first one then two then three then four
You can upgrade bownie farm by selling lots of farm products. Eggs Milk Mayonaise Butter Cheese Etc.
You have to sell products related to their shop to upgrade it. :3