Regularly check the health and wellness of each of your animals.
For this, rolls over a chosen animal and see if the health bar (top) and satiety bar (below) that appear, are green and filled to 100%. If yes, everything is ok!
If not, then you can remedy it by clicking the animal then clicking on the action icon "Feeding" and/or "Treat" .
For more detailed information, click on the "i" icon.
The type of exhibit Each animal belongs to one or more specific habitats, it's best to install it in an exhibit of the same type as its.
The design of the exhibit Decorate it with appropriates decorations for the animal.
Some are suited to all animals
(icons without outline) and others to those of a particular type
(icons with outline).
If in addition, there is a small yellow triangle in the bottom corner, then the decoration improves the wellness of a single animal, and if it's orange, then it will improve several animals's ones.
Examples!

Decoration suitable for ALL savannah animals.

Decoration suitable for forest type animal
(in this case, the Panda) 
Decoration suitable for many different types of animals.
Space available to it You must remember that for every species, there's a minimum and an optimum exhibit surface area.
The minimum surface area allow the animal to have a reasonable wellness. This minimum match with his size.
The optimum surface area will allow to have an improved wellness. This optimum is not indicate to you, you'll have to determinate it. That being said, know that it 's sometimes equal but oftenly higher than the animal size (rarely more than three time as much and never more than four.
Note!
- Squares with decoration on it, will not be counted in computing space.
- Avoids putting too many animals in a too small exhibit. Overcrowding is never good for the animals's wellness.
- Avoids also constructing exhibits too big in comparison to the animal's size that you place inside, it'll cost you unnecessarily money in upkeep costs.
- If you're place many animal in a same exhibit, you'll have to add the minimum surface area of each animal to know the minimum surface area needed to the wellness of all.
It works the same way pour the optimum surface area, that you can only do an estimation as long as you don't know the precise surface area.
Example!
- For 1 Panther (Size=2) :
Minimum space = 2 cases < Optimum space = ? < Max = 8 cases - For 1 Lion (Taille=3) :
Minimum space = 3 cases < Optimum space = ? < Max = 12 cases - For 2 Panthers + 2 Lions:
Minimum space = 10 cases ((2+3)x2) < Optimum space = ? < Max = 40 cases ((8+12)x2)
You'll understand that determinate the optimum space to the wellness of each species will be very important if you'll want to optimize to the best your zoo's superficy with a maximum of animals in their best wellness!
The cleanliness of the exhibit The more animals you have in an exhibit, the quicker the exhibit will become dirty.
Keep in mind to clean it regularly because neither animals, neither visotrs like a dirty exhibit!
Species with which it coexists Some species may not enjoy being in the same exhibit with others, especially if they are hungry. ;)