Q.sunflower pests
Some of the sunflowers in my garden have been defoliated – entire leaves eaten off. Some of the younger plants are completely defoliated (but then grow new leaves). Is it possible that squirrels, rabbits or other small animals could be biting off the leaves? Adjacent plants are not affected. Thanks.

There are actually a few pests that like to nibble on sunflowers. Here is an article that you may find helpful: https://www.gardeningknowhow.com/ornamental/flowers/sunflower/sunflower-problems.htm