Hello,
I started several butternut squash plants from the seeds out of a butternut. 3 of the seeds have produced butternut, 1 of the seeds has produced yellow squash and 1 seed has produced what looks like a zucchini. The leaves of the plants and the way they grow are completely different. What is happening? Are these mutant vegetables safe to eat? The leaves of the plant are not the same as a butternut. The plant does not vine. The plant itself looks like a zucchini too.

Apparently your butternut was pollinated by several different plants. It will be interesting to see what they produce. Do you have pictures?

I think it would be quite unusual for a butternut squash (C. moschata) to cross with a zucchini (C. pepo)... but I have no other explanation for what might be going on with your seeds and plants

You may have mixed up seeds.

as already said.. and, all safe to eat, just not sure what the flavor/texture will be.