Lol, I don't think you'll want squares or rounds. They're about 5'x4' and weight 1000-2000 lbs. Definitely wouldn't fit in your car. I'm not sure what they are meaning by a cube of hay. I know there are hay cubes for horses, which are small compressed blocks of hay, so not what you're looking for. If it's not that, it could be like half size bale. So flakes are what the bales can be broken up into for feeding. Generally 4 flakes will feed a 1000 lb. horse per day. There are about 12 flakes in a 50 lb bale. When you call asking about hay, ask how heavy the bales are, what quality it is - good quality horse hay, is it nice and green, has it been wet- don't want any moldy hay, is it weed free. You might be looking for something like a later cut alfalfa. It's actually lower in ptotein, more stemmy, and less nutritious, but typically earlier cuts tend to be more flakey, which I think that is what you are talking about when you say there's fluff. Early cut means the plant is harvested earlier in it's growth, later cut is that it growns longer, hence the thicker stems. There's also 1st, 2nd, 3rd cuts and that just indicates when in the season the hay was cut. If you find something that sounds good to you over the phone, you could always ask if they have a picture of it that they could email to you. I can't say how many times I've called about hay and they say it's good, and it ends up being crap. Generally, the more your paying, the better chance it has of being good.
I think you could fit a bale in your car. It would probably work the best if you brought a bunch of heavy duty garbage bags, cut the bale open(you'll need scissors or a knife), and split it up into 3 or 4 bags. Then your car won't get as messy either.
Edit: They'll be fine eating grass for a while. When looking for hay, if you try again, get them to send you a picture, and you don't want any special kind of hay. You just want premium quality alfalfa horse hay in a normal bale, that's a late cut. You could also call around to horse stables around your area and see if they'll just sell you a couple flakes. That might be the easiest. Then you won't have to buy a whole bale, and if it's a nice stable, they will usually have nice hay too. But if it just seems like too much at this point, the grass isn't going to hurt anything. They're nearly full grown anyways.
