When we lived in TX those were the things to have, the bale dollies/trailer! So cool!
I could never find one used and cheap enough to justify it because they were in high demand- hence the rolling the bale out of the pickup by slamming on the brakes..LOL!
Now we get the big 1200-1500 lb. Square bales and I have hubby throw a couple on the back of the hay trailer when he loads at a ranch that has good horse hay and I pull them off with the pickup and a chain in the driveway.
A tractor and a set of hay spikes are on my list to send to Santa :)
I DON'T LEAD 'EM AND FEED 'EM, I RIDE 'EM AND SLIDE 'EM.