“One day I want to buy a little farm in the country and grow vegetables and raise chickens.”

You and your boyfriend are having fun imagining what you will do when you retire. You say:

One day I want to buy a little farm in the country and grow vegetables and raise chickens.

one day

"One day" is a phrase that people use to talk about things that might happen far in the future. For example:

One day when you own a house of your own, you can make your own rules. But as long as you're living under my roof, you'll do as I say.

I really want to visit Russia one day.

the country

"The country" is an area where there are a lot of farms, forests, and very small towns. You usually compare "the country" to "the city":

I grew up in the country, so it's hard for me to even imagine what it's like to grow up living in the city.

You always have to use "the" when you're talking about "the country". If you don't use "the", people may think that you're talking about a country like The United States, Australia, China, etc.

raise (animals)

You can "grow" vegetables, but you can't "grow" animals. You have to "raise" them:

We're growing tomatoes, carrots, herbs, all kinds of stuff.

When I was a kid, my uncle used to raise sheep. 

To "raise" something means to help it grow. Things that you can "raise" include: 

• raising crops
• raising animals
• raising children

(something) and (something) and (something)

In written English, it's incorrect to use "and" more than once in one list. But in spoken English, it's common:

Let's see... I've been to Germany and Finland and Poland... Oh, and Turkey, too!