I don't know what sort of farm this was. The highlight of the day on the farm where I grew up was usually the scolding I got, if the cow kicked the milk bucket, or put her foot in the bucket. Of course, there were the guineas (annoying birds), the occasional cow that got loose, the goat getting loose, or the rooster on the rooftop, and things of that sort.
This MacDonald had himself quite a farm. The quartet stopped by and sang some, including this song. One of the quartet members is very good with sounds. For example, in past performances of this song, he could imitate a chicken after it laid an egg, or if there was a predator, or if it was establishing pecking order. He could mimic any farm animal sound, and lots of other creatures, as well.
Ol' MacDonald's farm went through some changes, this go-'round. No chickens, cows, or any of the usual things. Nope, probably the old man himself skadoodled. This farm was home to a screech owl that'd make the hairs raise on the back of your neck, send the dog into hiding, and give the kids nightmares. But that's not all. This farm must've been flooded, because it's also home to a humpback whale. That darn whale didn't want to be a loner, apparently, because he made a tolerable facsimile of a mating call. Probably not the company he wants, but the farm was also home to one T-Rex. And he's a-hungry. That T-Rex call, with the amplification of the sound system, was a fearsome thing.
I have nothing against farms, but I'm glad this one was just a song.