Is it in the sun? Are you watering it? Why are you hand pollinating? Mother Nature usually can handle that herself.

My zucchini get plenty of sun, I water frequently but not too frequently (the leaves are extremely healthy and green) and I am hand pollinating because I never got one zucchini last year from my plants and I do not have a large population of bees. By the way, I have several squash plants and they are doing beautifully. I am beginning to feel as that zucchini is just not my thing.

Zucchini puts out many non fertile blossoms for every fertile one. You can tell which is which by the small swelling at the base of the blossom. Don't bother hand pollinating the ones without that bulge at the blossom's base....it won't ever fruit.
Linda C

I am only pollinating the female blooms (the ones with the squash on the end).

How about posting your question on the fruits and vegetable forum?