ok well this may be a bit basic, but ive found in chloes class recently we have ahd a few issues with ppl bringing their pets to class for show and tell.
. please NEVER EVER EVER bring a pet that bites, it doesnt matter if they r in

a cage or not.
. make sure all pets r deflead and vaccinated or treated for mites depends on what sort of animal u have for each treatment.
. explain to the children how to hold the animal if its going to come out of the cage.
. ask the teacher at least a week in advance, this way he or she can check all kids for allergies and set up a time when the children r most settled.
. try to explain how much work each pet is and how to take care of them properly eg:how much they cost to look after, the amount of time u have to spend with them each day.
.please dont take an animal that is not used to being around alot of ppl to a school, if u see the animal start to get agitated at any time remove them from the classroom.

good luck try to make your pets visit an enjoyable and educational visit that way less animals will be taken by families unable to care for them.