Here are photos showing how I put holes in clay pots to use in setups like this one.
If you want a hole midway up the pot (rather than along the edge), it's also possible to make a hole using a "core" drill bit or forstner drill bit (search it on Google images, if you don't know what these are).
IMPORTANT: the clay chips more easily if you soak the pot in water overnight before chipping.
Be prepared for occasional mistakes. If the whole pot cracks in half (and it does sometimes), you can still use the broken pieces as animal hides. I find this works best if I chip the clay a little bit at a time. I generally use the edge of the pliers to smooth down the broken edge a bit after the hole is the size I want.
If you want a hole midway up the pot (rather than along the edge), it's also possible to make a hole using a "core" drill bit or forstner drill bit (search it on Google images, if you don't know what these are).
IMPORTANT: the clay chips more easily if you soak the pot in water overnight before chipping.
Be prepared for occasional mistakes. If the whole pot cracks in half (and it does sometimes), you can still use the broken pieces as animal hides. I find this works best if I chip the clay a little bit at a time. I generally use the edge of the pliers to smooth down the broken edge a bit after the hole is the size I want.