Feeding animals hay can be challenging at times, I normally feed square bales because they are easier for me to store. I do prefer to feed round bales when possible but I can only store three small bales compared to 150 square bales. Normally for my two horses I feed half a square bale a day with grain or one small 4×4 round bale lasts about two weeks. The 4×4 type bale I get I can only find in one place. Most of the hay you end up buying comes from farmers that cut excess for sale, they have bigger equipment and don’t want to mess with feeding their 100 cows any more than they have to so they use a big baler.
For now my tractor is down so I can’t use it to move round bales, I can move the smaller ones by myself.
With the smaller bales they can be rolled into the back of a truck using 2×6’s or an ATV ramp.
Food for thought, hay is best covered if it is not going to be eaten immediately. Hay out in the weather will have a loss of nutritional value through leaching of digestible nutrients (http://www.uwex.edu/ces/forage/pubs/haystorage.pdf).