tl;dr The words mean exactly what they say: Mrs Collins still finds pleasure in tending to the parishioners and the chickens.
Deets. Charlotte Lucas has made a choice very different from the one Elizabeth has made. They are both intelligent young women with abundant common sense but no family wealth. Their lack of fortune means that their only hope for future security is marriage to a man who can provide for them. Elizabeth has the advantages of youth and beauty, but Charlotte has never been considered good-looking, and is seven years older than Elizabeth. She therefore chooses to woo and marry Mr Collins despite knowing how foolish he is, and how tedious a companion he would make. All of this is first explained when she accepts his proposal of marriage, less than a week after Elizabeth has turned him down:
The whole family in short were properly overjoyed on the occasion. The younger girls formed hopes of coming out a year or two sooner than they might otherwise have done; and the boys were relieved from their apprehension of Charlotte’s dying an old maid. Charlotte herself was tolerably composed. She had gained her point, and had time to consider of it. Her reflections were in general satisfactory. Mr. Collins, to be sure, was neither sensible nor agreeable: his society was irksome, and his attachment to her must be imaginary. But still he would be her husband. Without thinking highly either of men or of matrimony, marriage had always been her object: it was the only honourable provision for well-educated young women of small fortune, and, however uncertain of giving happiness, must be their pleasantest preservative from want. This preservative she had now obtained; and at the age of twenty-seven, without having ever been handsome, she felt all the good luck of it. The least agreeable circumstance in the business was the surprise it must occasion to Elizabeth Bennet, whose friendship she valued beyond that of any other person. Elizabeth would wonder, and probably would blame her; and though her resolution was not to be shaken, her feelings must be hurt by such a disapprobation.
Jane Austen, Pride and Prejudice, chapter 22. 1813. London: George Allen, 1894. Available on Project Gutenberg. (Emphasis added.)
When Charlotte explains her acceptance of Mr Collins to Elizabeth, the following dialogue ensues:
“you must be surprised, very much surprised, so lately as Mr. Collins was wishing to marry you. But when you have had time to think it all over, I hope you will be satisfied with what I have done. I am not romantic, you know. I never was. I ask only a comfortable home; and, considering Mr. Collins’s character, connections, and situation in life, I am convinced that my chance of happiness with him is as fair as most people can boast on entering the marriage state.”
Elizabeth quietly answered “undoubtedly;” and, after an awkward pause, they returned to the rest of the family. Charlotte did not stay much longer; and Elizabeth was then left to reflect on what she had heard. It was a long time before she became at all reconciled to the idea of so unsuitable a match. The strangeness of Mr. Collins’s making two offers of marriage within three days was nothing in comparison of his being now accepted. She had always felt that Charlotte’s opinion of matrimony was not exactly like her own; but she could not have supposed it possible that, when called into action, she would have sacrificed every better feeling to worldly advantage. Charlotte, the wife of Mr. Collins, was a most humiliating picture! And to the pang of a friend disgracing herself, and sunk in her esteem, was added the distressing conviction that it was impossible for that friend to be tolerably happy in the lot she had chosen.
Elizabeth's visit to Charlotte after her marriage allows her to see that in fact, Charlotte is perfectly content with her lot. She arranges her day so that she has to spend as little time with her husband as possible:
The chief of the time between breakfast and dinner was now passed by him either at work in his garden, or in reading and writing, and looking out of window in his own book room, which fronted the road. The room in which the ladies sat was backward. Elizabeth at first had rather wondered that Charlotte should not prefer the dining parlour for common use; it was a better sized room, and had a pleasanter aspect: but she soon saw that her friend had an excellent reason for what she did, for Mr Collins would undoubtedly have been much less in his own apartment had the sat in one equally lively; and she gave Charlotte credit for the arrangement.
The unromantic and practical-minded Charlotte has made the best of her situation. She is even an excellent wife to Mr Collins, running his household efficiently. She does not look to her husband for companionship or even common sense; instead, she is content with the bargain she has made, of marriage to a pompous and ill-bred man in exchange for domestic comforts. This is a bargain Elizabeth has explicitly rejected, and she is initially unwilling to believe that Charlotte could be content with it. But Charlotte does have financial security that she would not otherwise have had, and her marriage brings her other consolations too. As the wife of the parson, Charlotte would be a person of some importance in the village. She would be the person parishioners, particularly the women parishioners from poorer families, turn to for advice and comfort, and she would be able to help them with charity or care if their poverty or health so demanded. Finally, she has her own domestic chores, such as keeping chickens for meat and eggs, that also occupy her time and attention, thus distracting her from her tedious husband. Despite the shortcomings of Mr Collins, her parish and her poultry allow Charlotte to be satisfied with her situation.