There are many opinions on how zucchini plants should be grown properly. This year (the first with my very own garden) I think I have made some mistakes. The first and probably biggest mistake I have made is letting my plants grow into zucchini monsters (see above photo). I always knew zucchini plants get big and take up lots of space. As they got bigger and bigger I noticed that the base of the plants looked crowded. That didn't seem right to me so I started to do some reading. Turns out there are many websites and gardening blogs that recommend cutting back some of the larger leaves to improve airflow to the base of the plant and allow sunlight to reach your fruits. Having good airflow to the base of the plant is important to preventing powdery mildew (which is common on zucchini and cucumber plants) and prevents fungi and rot.
Determined to raise healthy zucchini I decided to prune my plants and hope for the best. I have no idea if I did it properly. My research prompted me to cut back the largest leaves at the base of the plants below the fruit. I discovered, to my surprise, that the giant leaf stems are completely hollow and a have a consistency similar to celery. Because the stems are hollow they should be cut back as close to the base of the plant as possible so they wont be a breeding ground for pests or disease. Doing this is not as easy as you would think, especially if your plant is monstrous and it is difficult to get to the plants base.
In the end I took out many of the leaves that were shading the fruit and, I think drastically improved airflow to the base of the plant. I hope my plant continues to grow and be healthy but we'll see...
Update: 7/6/2020
The zucchini growing is not going well. Cutting back the larger leaves and letting more air get to the base of the plants was a good idea. However, I think I waited too long to hack away at it. The base of the plants are such a tangle of leaves, stem, and zucchini that I can't even get to the fruit. Much of it is squashed (no pun intended) underneath the main stem and other leaf stems. It seems like I have to cut back leaves every day to get at the fruit. So far my four plants have yielded only four good zucchini, many others have rotted on the vine before they ripen. Lesson learned for next year!