>1 animal single encl Observing more than one animal in a single exhibit can be approached in a number of different ways, depending on what you are trying to test/observe and how many animals there are in the exhibit. For example, if the exhibit contains only two animals, taking an average of this would not be meaningful for analysis. If however, you are comparing treatments (enrichments, for example) on behavioural response x, and the expected effect size (in other words, the difference between the treatments) is very large, you may get away with using relatively few subjects.

An alternative is to choose one focal individual, and follow that animal (identified by markings, perhaps) and use the single-case design described here.

Typical designs include (but are not limited to) phase designs such as:

AB
ABA
ABAB

where 'A' is baseline and 'B' is treatment x.

These types of design are very useful as the allow you to return to baseline to ensure that any effects of treatment are not due to uncontrolled factors.

Finally, don't forget that as you have not used random sampling (i.e., all of the animals have come from one zoo) you cannot generalise your findings beyond this study! To do this, you would need to collect a random sample from the population.