Technically true, but I think we all understood immediately that it was more than one farmer.
All correct translations should be reported. According to wordreference (and we have some confirmation from our spanish-speaking friends here) feria can also mean: farmers' market, trade show, trade fair, funfair, and festival. They didn't mention carnival but that seems close enough to funfair or festival that it should be accepted too.
"In the senses of "fair" (market) and "fare" (food and drink), fayre is still often used to lend an air of history or tradition, particularly in the United Kingdom; for example, a school's "summer fayre" or a university's "freshers' fayre", and "traditional English fayre [cuisine]".
So it may be in usage, but I think with a deliberate intent to sound archaic. Is there a name for that kind of word?
You're right, Paul, it sounds more natural too. While I wasn't at all debating the reply above to the original asker, I thought it might've been helpful to point out that DL also accepts the continuous version because when we use the simple present in English, we only state a fact; stating a habitual action, while when Spanish speakers use it they could be referring to the immediate future, like we do in English using the continuous. A friend of mine from Puerto Rico always says, "I call you tonight" or "I go by your house tomorrow" when she meant to say, "I'll/I'm going to call you tonight" or "I'll/I'm going to come by your house tomorrow", respectively.
It's saying that his cousins go (or are going) to the fair where there's a gathering of amusements and stalls for entertainment, like a carnival; although a "fair" has a few other meanings too, like in towns where folk gather to promote or sell their agricultural produce, livestock, etc.
Whenever I choose to take a peek at the drop-down hints, I tend to get them wrong more likely than not. I was going to put My cousins go to the fair, but since the drop down under "van" listed "go out" I decided to try my cousins go out to the fair. It was marked wrong. >:-(
In SPAIN, Feria means exhibition or fair of any kind - funfair, agricultural show, and a two week long festival! https://fiestas.yecla.es/category/feria-de-septiembre/ We also have a permanent building and institution - Feria de muebles, de Yecla http://www.feriayecla.com/, which exhibits locally designed and fabricated furniture.