No, leaves are fine............i tried vhs tape, tinsel, and old cd's hanging from my cages............we'll see what happens.........

Hard to tell but must be an animal of some kind. Look for the droppings. Scat will tell you whats doing the eatin'

I have the same problem - usually happens at night. I have heard that squirrels eat them, but I've been told rats do too. Raccoons do not like tomatoes. I have heard blood meal works and you can get it at Home Depot or any home improvement store or garden store.
However, we still are not sure what is eating our ripe tomatoes. They start to turn red and BAM! The are found tossed to the ground with just a couple bites taken from them. This may sound strange, but it worked for a friend of ours this winter and I'm going to try it if the blood meal doesn't work. They had squirrels in the attic. Nothing would keep them away, except...they were told to tie a piece of cloth with female human urine on it (female scent is stronger than male.) Put it inside a knee high and toss it where they get in, reluctantly they did this (they were at their last rope) and guess what - it worked! The squirrels never came back all winter!!
We have a fence around our tomatoes - it doesn't touch them and I'd tie it above the ground. If it worked in the attic it has to work in the garden.

Could be Oppossums!!

My father had an animal taking his tomatoes. It would spit out the green ones, and eat the rips ones. He set the catch em live trap and turns out it was an oppossum. He released it miles away, but there are still others around.