We have deer in our neighborhood that have eaten quite a few new potted tomato plants in the past.
What we did this year to save the crop was place the pots in the back of our yard against a wire fence and cover them with bird netting propped up by tall narrow driveway markers used to tell snowplowers where the driveway is after a snowfall. And that's not all. We plant a marigold with each plant to ward off bugs and periodically sprinkle shavings of Irish Spring soap in the area. This year we also enjoyed Christmas in JUne, July, and August by placing solar powered fairy lights on a Hemlock Tree nearby.
At dusk the tree lights, set on blinking mode, go off and on through the night.
Knock on wood, so far we have had no damage to the tomatoes.