Everything I've ever read about planting squash says to create a hill 12 inches high and plant 3-4 seeds in it. But I don't recall anything ever saying why. Why hills instead of just rows? I'm starting mine indoors in single peat pots. I want to get a head start.
I'm not sure the Why of it but here where we tend to have dry summers we do NOT plant on hills. It's too hard to water. 8)
To my knowledge hills heat up faster which helps germination and also they allow for extra drainage. This method no doubt benefits zucchini so that's why it is mentioned
I didn't even plant any this year, it always takes up so much of my available space and there's folks at the church who try to get rid of extra ones free during harvest times anyway... I hadn't thought about why they recommend hills like that, the heat and drainage issues make a lot of sense.
The water always runs off the hills and pools at the bottom. We're in a drought-prone area, anyway, and zucchini hills are frustrating. This year I think I'll try straight rows instead. Last year the squirrels got all the zucchini seeds or just chomped off the squash sprouts as soon as they popped up. This year I'm planting them indoors.
Hills, schmills. Rows work just fine. To deter little pests, try planting your zuke & squash seedlings in the tubes from TP rolls. Sure works on the cutworms, and it may help with squirrels. Also, hot pepper is a great deterrent for squirrels.