In "A Jury of Her Peers," what aspects of the Wright’s farm suggest that this was not a happy place for Minnie?

When Mrs. Hale gets to the Wright property near the start of "A Jury of Her Peers," she notes the lonely and isolated appearance of the farm. The narrator writes,

Mrs. Hale scarcely finished her reply, for they had gone up a little hill and could see the Wright place now, and seeing it did not make her feel like talking. It looked very lonesome this cold March morning. It had always been a lonesome-looking place. It was down in a hollow, and the poplar trees around it were lonesome-looking trees.

Mrs. Hale feels silenced by the look of the place, and the word "lonesome" is repeated three times in the short paragraph. This sets the tone for the rest of the story. The further sense of Minnie Wright's loneliness is described when Mrs. Hale hesitates to open the door:

Even after she had her foot on the door-step, her hand on the knob, Martha Hale had a moment of feeling she could not cross that threshold. And the reason it seemed she couldn't cross it now was simply because she hadn't crossed it before.

Mrs. Hale does not want to go into the house, and the reason she gives is that she has not visited before. Minnie's lack of friendly visitors both suggests her isolation and Mrs. Hale's guilt for contributing to that isolation.
While exploring the house, the men point out that they had found Minnie sitting in a rocking chair. It is described by the narrator as follows:

Everyone in the kitchen looked at the rocker. It came into Mrs. Hale's mind that that rocker didn't look in the least like Minnie Foster—the Minnie Foster of twenty years before. It was a dingy red, with wooden rungs up the back, and the middle rung was gone, and the chair sagged to one side.

Mrs. Hale notices that the rocker does not match the former personality of Minnie, so she must have changed for the worse, or she does not feel at home in her surroundings. The description of the "dingy" color and "sagg[ing]" chair that stands in a state of disrepair adds to the depressing mood that pervades the farm. It is difficult to imagine anyone living a happy life in that setting.
A conversation between two characters later in the story furthers the idea of the dour and lonely life on the farm but also shifts the attention from Minnie to her husband, the murder victim, and the role he played in contributing to the homestead:

"It never seemed a very cheerful place," said she, more to herself than to him.
"No," he agreed; "I don't think anyone would call it cheerful. I shouldn't say she had the home-making instinct."
"Well, I don't know as Wright had, either," she muttered.
"You mean they didn't get on very well?" he was quick to ask.
"No; I don't mean anything," she answered, with decision. As she turned a little away from him, she added: "But I don't think a place would be any the cheerfuller for John Wright's bein' in it."
"I'd like to talk to you about that a little later, Mrs. Hale," he said. "I'm anxious to get the lay of things upstairs now."

The exchange between Mr. Henderson and Mrs. Hale begins with Mr. Henderson basically blaming Minnie for the inhospitable feel of the home: "I shouldn't say she had the home-making instinct." Mrs. Hale quickly turns this idea on its head, saying that John Wright certainly wouldn't have done anything to make the home happier or more welcoming. This eventually leads to the discovery by the women of the dead bird that symbolizes Minnie. This symbol suggests that Mr. Wright oppressed Minnie and didn't allow her to be herself. When he killed her bird, she snapped and killed him. Mrs. Hale expresses her empathy for Minnie:

Mrs. Hale had not moved. "If there had been years and years of—nothing, then a bird to sing to you, it would be awful—still—after the bird was still."

Mrs. Hale understands how changed Minnie was by life on the Wright farm and with her husband. She is compassionate and also feels guilty that she did not do more to ease Minnie's troubles. Ultimately, she protects her former friend because she can understand why Minnie was so desparate to escape her lonely prison of a life.