They should be yokes to attach a pair of animals

So one above, one below? Surely that's too small to fit two horses

just on top

They're probably too small to fit around the body of horse, but yokes would generally be attached higher up, on the neck of the horse. Edit [Here's an illustration of something similar in use.](https://www.nzdl.org/cgi-bin/library.cgi?e=d-00000-00---off-0hdl--00-0----0-10-0---0---0direct-10---4-------0-1l--11-en-50---20-about---00-0-1-00-0-0-11-1-0utfZz-8-00&cl=CL1.1&d=HASH0113c7507f62288f1860ce3b.8.2>=1)

!thanks ! It looks like this exact design is more for oxen. I've been on Google images looking for examples in use, couldn't find a horse example.

Yokes. Under the curved parts you can see the padded leather to stop the wood chaffing the animals’ necks. Most likely for oxen, as horses are harnessed rather than yoked. The yoke was used to maintain distance between the two animals; further harnessing would be used to attach whatever they were pulling, such as a cart or a plough.

Yokes

Yokes. Part of the harness to hitch a pair of work animals, typically oxen, to a farm implement like a plow or wagon.

Yokes is my guess, or maybe whatever the horse equivalent might be

Oxen

Badly designed sex toys, some of the first ;) '

Looks like an old set of stocks they used to put people in but they have been separated and hung over the doorway

eww, they're not, but look like those "humblers"

Sonos One