I would say depends is the answer. You indicated 'small herd and only 2-3 bales, which has me leaning towards "no", but that is up to you. As long as you do not place bales in the exact same location one after another, I would say leaving the bales intact would be fine. Yes, the bales leave a 'bale scar' for a year to a year and a half, but those are more an aesthetic effect than a resource concern. I don't know the cost of a hay unroller and also don't know what a 'threshold' number of bales/herd size would be to consider a hay unroller purchase. I would think it would be more than 3 bales.
Kinda funny. I just typed this 2 hours ago as an answer to bales vs unrolling to another forum participant. It applies here as well:
If you go with placing your hay that you feed in the winter within the pastures, I wouldn't use bale rings. They are expensive and don't really do a whole lot, maybe save a bit of waste, but it isn't really waste in a pasture if you consider the fertilizer value of the hay. As for placing whole bales vs unrolling, there are a few things to consider. Unrolling a bale takes some time, maybe not a lot, but there is a time factor. Yes, the hay gets spread a bit more. However, if you are placing whole bales randomly and NEVER IN THE SAME SPOT, the spread is nearly as good. As for whole bales creating a 'muddy spot', yes they do. I've never had anyone consider this to be a real significant issue as it heals in a year to a year and a half, other than maybe just looking a bit 'messy' for that time. One thing to possibly consider, and I chalk it up to a freak accident. I worked with a producer one time who told me he fed whole bales. In doing so, the way the cows ate the bale (one instance only) the bale ended up collapsing on top of a calf and suffocated it. Again, a freak accident, but worth noting as a possible consideration, especially since you only have 6 cows, hence, 6 calves and a single loss is significant. There is some merit in keeping your hay dry until ready to feed. This may be offset by the difficulty of trying to get the bale to the location to feed when needed such as dealing with mud or snow, which you probably don't have much of (the snow anyway).