Have you installed foundation drainage and backfilled yet? Is there provision for interior drainage? How thick is the hay at the inside face of the foundation wall?

What location?

The main problem is that an exposed foundation can be damaged by frost heave when the soil freezes.

Once the building is finished the back-fill limits the frost depth on the outside, and the heat on the inside.

Short of burying the foundation (inside and out) there is not a lot you can do if you are in an area that freezes.

You sort of just have to take your chances, and be prepared to make any required repairs.

Hay (rarely used) or straw that is not covered with a waterproof covering easily becomes saturated with water and is less than useless. Plus it's a messy job to haul it out it in springtime. Instead, builders often use concrete insulating blankets, which are reusable and simply roll up after use.

Too bad you weren't close by a few years ago when I gave away about 10 of them after a job. The customer paid for the blankets, but come April we couldn't even sell them for a sawbuck.

Here is a link that might be useful: Concrete insulating blankets

unpoured floor = bare soil? If so, there's no reason to cover that. If the hay is still dry, pile it up at least three feet high, up to two feet wide on the interior of the foundation walls, then cover it with wighted-down waterproof tarps or attach the tarps to the walls and ground.

If the wall is not backfilled, backfill it above the frostline in your area, but only after it is braced on the inside.

The only time I didn't use blankets is when a friend's barn lost its roof and the winter hay supply for their horses got too damp to use. Insurance paid them for a new supply and I got a cube van full of the still dry bales on the bottom.

Once you get the protection in place, monitor through the winter.

Thanks for the responses! To answer some questions, the house is located in oxford, ct. The floor is not poured but there is stone. The walls are backfilled and the curtain drains are installed however there are no basement drains. (I was hesitant to backfill but our builder spoke with the guy who did the foundation and he said it wouldn't be a problem. At the time I also thought my house would sell before winter). I covered the whole floor with tarps I thought this might help with the insulating and the removal of hay in th spring. Right now there is about a foot of hay covering the whole floor up to the walls. I had some leftover bails which I lined around the interior walls which got probably half the walls lined. That was where I left it yesterday before I ran out of daylight. Thanks again for your help.

Not only does wet hay not insulate, it has a higher chance of spontaneous combustion.

I was hesitant to backfill but our builder spoke with the guy who did the foundation and he said it wouldn't be a problem.

If I had a buck for each time I hear "no problem" when all the literature and experience says the contrary, I'd be rich!

Here is a link that might be useful: Backfilling Basics

Worthy, Thank you for the link. I guess the only thing that might be in my favor at this point is that I only have one straight wall that is longer than 24' it is 24'6" and it is on the side of the house where the foundation is stepped to a walk out basement. I plan on getting back to the foundaton before the hay gets wet to spread it and tarp it the way you suggested in your previous post.