Neighbors squash plants are turning yellow. Are they supposed to be yellow? She left for a week and did not water. They have decent size zukes on em

Nope - definitely not supposed to be yellow.

That looks mighty dry to me. At this time of year if I were going away for a week & didn't have anyone to water for me, I'd have watered very deeply before I left & mulched everything as heavily as possible.

Thanks.

She is a Roundup gardener as well.

Well, there ya go! My neighbor's garden looks sickly also, and he's the Round-up man as well. His cantalope died completely, as did his eggplant. The zuke doesn't look too good.