We buy hay. We need to move bales. Bales can be 800-1200 lbs.
It is understood you need to move bales. Do you need to lift bales in order to stack them two or three bale rows high?
An open station tractor with a bare weight of 3,700 to 4,000 pounds can lift and move 800 - 1,200 pound round bales using a bale spear on the Front End Loader and stack bales two high on level ground if you purchase a FEL with sufficient lift capacity 500mm forward of the pivot pins. However, the tractor will feel very tippy to a neophyte operator lifting bales to stack.
An open station tractor weighing 3,700 to 4,000 pounds can transport 1,200+ pound round bales safely with a Three Point Hitch mounted (rear) bale spear but can only lift bales a few inches. Transport but no stacking. The tractor is stable because the bale weight is low and bale weight is carried on the large, rear tractor tires, which do not pivot/steer.
This is the mid-weight category of compact tractors, a high volume segment. Every tractor manufacturer produces an economy model and a deluxe model in this weight range. Horsepower options range from 40-horsepower to 60-horsepower in this weight range.
A tractor with a bare weight of 3,700 to 4,000 pounds is suitable for actually working 10 to 25 acres of farm acreage. Working acres, not total acres.
For safety most recommend a 5,000 pound bare weight tractor for moving and lifting bales heavier than 1,200 pounds using a bale spear on the Front End Loader and for safely moving/stacking 1,200 pound bales by inexperienced tractor operators using a front bale spear. A 5,000 pound bare weight tractor can stack round bales at least three high.
A tractor with a bare weight of 5,000 pounds is suitable for actually working 20 to 40 acres of farm acreage. Working acres, not total acres.