Tate used bloodhounds to search for the culprits, and after the dogs circled the Barber house several times, Heck guessed the truth. The story serves several purposes. It is the primary reason why Maycomb's next Halloween was scaled down and the pageant was being held at the school, givingJem and Scout their excuse to walk to and from the school that night. In addition to injecting a bit of humor into the story before the tragic events of Chapter 28, it also allows Harper Lee to introduce another pair of unusual female characters while further developing her theme of prejudice against social outcasts or outsiders.  

Jem finds a hair in his armpit. In his effort to show it off to Scout, she can't even see it. The conversation goes into a 'where is it?' discussion and we see the innocence and excitement of puberty for one, while the other is not quite repulsed but has a 'whatever' type attitude.

The reader, being old enough to understand puberty, has to laugh. He's proud of something so minimal.

This lightens the mood after all the intensity of the news of Tom's death, the children and adults in the Finch home dealing with it in their varied ways, and this growing feeling that Bob Ewell is out to get someone and we have yet to learn who.

It it put in a pretty crafty spot because it takes away suspense just before there is about to be a lot of suspense in the last half of chapter 28.

It's almost Halloween and Mrs. Merriweather writes a pageant about the history of Maycomb and its various agricultural products. The humor comes from the fact that Scout will play a ham. Her costume, made of chicken wire wrapped with brown cloth is so clumsy that the can't put in on or take it off by herself. It comes to her knees and she can even use her arms because they are pinned down by the costume. She also can't see well enough to walk to the pageant by herself. Jem will accompany her. This description is important for two reasons. First, it gives some comic relief to two ominous things Scout has reported in this chapter. She recounts how Bob Ewell tries to get a job and was fired for being so lazy. He blames Atticus for losing his job. Then, Ewell starts yelling insults and following Helen Robinson to work. Link Deas has to threaten to call the sheriff in order to stop Helen's harassment. However, thinking of Scout in that ridiculous costume helps break the ominous tone. It also helps set up the next important episode in which Jem must fight for his life and Scout is prevented from being hurt by the strength of the costume.

There are two somewhat comic episodes that take place in this part of the story. One is the relating of the previous year's Halloween when several local children play a prank on two elderly deaf women. They hide the women's furniture in their basement. The women call for bloodhounds to find their furniture, but of course, they fail to pick up the trail. The furniture was eventually found, but not before a lot of aggravation. As a result, the adults of Maycomb County decide to hold a Halloween pageant this year to keep the kids out of trouble. Whether or not the furniture/bloodhound incident is comic or not depends on one's point of view. Taking the side of the teenage pranksters it might seem comical. However, from the point of view of the old women and Mr. Tate who went out of his way to get the dogs, it seems rather cruel. The incident serves to explain the reasons for hosting the pageant the next year.

There is another comic episode related near the end of To Kill A Mockingbird involves Scout's blunder at the town's Halloween pageant. Scout is dressed up in an elaborate and uncomfortable ham costume representing one of the county's agricultural products. Despite the cumbersome costume, Scout falls asleep backstage and misses her cue. This causes Miss Grace Merriweather, the pageant's host, to repeatedly shout, "Pork!" without a response.

This little episode takes place as tension is building in the story. Earlier in chapter 27, we learn that Bob Ewell has been causing a lot of trouble. He has been blaming Atticus for losing his WPA job. He has been harassing Helen Robinson. He is also suspected of trying to break into Judge Taylor's home. Given Ewell's disdain towards Atticus, it seems very likely that he will target the Finch family for some sort of revenge. The comic episode with Scout and the ham costume likely serves as a break in this tension. It temporarily puts the reader at ease in order to increase the tension when Scout and Jem are chased by a strange assailant in chapter 28 who turns out to be Bob Ewell.

Chapter 27 isn't particularly funny for the most part, as some ominous foreshadowing begins to surface in the aftermath of Bob Ewell's trial.  Ewell gets a WPA job, loses it in a matter of a few days and openly blames Atticus, who, of course, had nothing to do with it; Judge Taylor hears a prowler in his home late one evening; and Ewell begins following Tom Robinson's widow, Helen, as she walks to work, whispering obscenities at her, and ceasing only when Link Deas threatens to have him arrested.  Atticus, ever faithful in the essential goodness of human nature, is nonplussed, but Alexandra expresses concern for his safety.  The comic relief that precedes the climactic final chapter involves Miss Grace Merriweather's agricultural pageant to be performed for the town on Halloween night.  Scout is representing Maycomb County pork, but falls asleep backstage in her unwieldy wire costume, leaving Miss Merriweather to call "Pooorrrkkkkk" with no Scout appearing.  She does finally wake up and tumbles onstage to her own embarrassment and the crowd's delight.