Depending on the lives of the animals for which they care, handlers usually work both indoors and outdoors. But the indoors is often nothing more than an animal shelter, and not much different from the pens outdoors. Be prepared for smelly, messy, and dusty environments; if you have allergies, they'll be under constant assault. It will be both to your benefit, and the animal's, to make sure you work in well-ventilated areas. Some institutions, particularly animal research labs, require handlers to have immunizations and physicals before working with the animals. In addition to allergies, there is some danger of diseases transferred from animals to humans. These risks can be lessened with protective clothing like lab coats, gloves, and ventilated hoods.
The temperament of your animals will also affect your work environment. Handlers must be prepared for occasional scratches, bites, and kicks from animals with even the best dispositions. Though some animals can be very noisy when disturbed, handlers attempt to keep their animals' surroundings quiet and calm.