I know I've posted this before. I usually buy the cubed, raw butternut squash at TJ's or Costco. I then toss it with a small bit of EVOO and then throw it in the oven on a stone. When nicely colored and tender, I cool it and pack in snack-size baggies and toss in the freezer. The advantage to this is I feel the pumpkin releases so much water when it's frozen. Sadie gets this at dinner on top of her kibbles. I just take one baggie out and that lasts for a few days. When it's empty, that same night I take the next baggie out of the freezer and put in the frig. That way it's ready to go for the next dinner. The roasted squash has already given up some moisture, so it's not as weepy as the canned pumpkin is when it thaws.
I think a yellow squash is a yellow squash, so I think both pumpkin and butternut produce the same effect. She loves pumpkin, too, but with one dog a can lasts too long. I have frozen it in single serving sizes, but then I have to thaw it before I put it on her kibbles. I know that isn't a requirement for her, but I don't like the thought of thawing pumpkin on my carpet.