An ancient cave cow comes to attack the barn animals! Meanwhile, scientists kidnap Otis, thinking he's really Cave Cow.

In order to celebrate Otis' birthday the animals trick Farmer into going to Turnip-Con for the weekend. However his plans hit a snag when that very same weekend the Beady's nephew, Eugene, comes for a visit.

When the farmer is seen with what appears to be a barbecue grill, they become afraid that the farmer plans to eat the animals, so they escape the farm on a hot air balloon. They ended up landing in a golf course and mistaken it as their new paradise.

Otis and Pip pretend to be superheroes Cowman and Ratboy, but the other animals are not fond of their antics. Fortunately, when Otis and Pip rescue the Pizza Guys from falling off a cliff, the animals decide to join them as superheroes.

After Otis saves Duke's life by pushing him away from a falling amplifier, Duke begins getting loyal to Otis and becomes devoted to helping Otis doing everything, but Otis soon becomes annoyed when Duke goes overboard.

When Pig's truffle pies become a huge hit in the barnyard, the animals decide to use Pig's pies to sell them to the humans to make money, but Pig quits when the animals begin to get greedy with trying to make money, especially when a celebrity comes to buy the pie recipe from them.

A space test monkey named Bingo crash-lands in the barnyard. The animals decide to let him stay in the barnyard, but Bingo is unsatisfied with the fact that Otis is the leader, so he tries to get rid of Otis so he can become leader.

Otis' pranks and Abby's driving lesson has Mrs. Beady sent to a mental institution. Feeling guilty, the animals try to rescue her, much to their dismay: Mrs. Beady's doctor wants to put her on a brain transplant when he thinks Mrs. Beady has "crazy brain" because she sees the animals out the window.

The animals are unable to have Saturday night parties because of the farmer constantly weeping about his lost wife. Otis finds him the perfect girlfriend to make him feel better, but they then realize that she is trying to get rid of the farm animals by kicking them out of the barn and take it over (forcing the animals to stay in the hen house which explodes because of the max capacity of the animals in there). So they dress Pig as rich man to lure the woman away from the barnyard, but Pig wouldn't lie and he confessed to her, which makes the woman leave the farmer. In the end, the animals get to have their Saturday night parties, Pig is heartbroken (which he stops after a few minutes), and the farmer went on a cruise with some ladies.

When Otis gets a hypnosis kit, he accidentally hypnotizes himself so that he tries to destroy the farmer whenever he hears the sound of a bell. Now, the other animals must try to protect the farmer while trying to cure Otis at the same time. But every time Abby tries to stop Otis from hurting the farmer, he thinks she is hurting him.

With Peck nowhere to be seen and Freddy seen lying on Peck's feathers, the animals conclude that Freddy ate Peck and plan to ban Freddy from the barnyard (Duke locks Freddy in a 'scented' pet carrier to attract the pet store truck driver so Freddy would be adopted). Otis is determined to prove that Freddy is innocent, however.

Otis is embarrassed when Abby repeatedly beats him in the Barnyard Olympics, so he tries to find Abby's weaknesses and use them to his advantage.

To get revenge at Bessy's insults, Otis tries to humiliate and embarrass Bessy, but at every attempt, the prank backfires. Bessy subsequently gives Otis a real (and humiliating) prank that ends up him and Pip covered in honey and seeds.

After Otis accidentally destroys the barn's safety film, he must make a new one, which he puts a lot of action and suspense in. When the other actors quit because of the dangerous stunts, Otis must make it on his own, and accidentally rises the barn into a tornado. In the end, Bessy makes the safety film all about Otis' unsafe antics.

Otis is excited because favorite country music star – Stumpity Joe – is coming to town. However, when trying to speed up crop collecting for the farmer to leave, he accidentally injures the farmer. Now, the animals must do all of the farming, or else the farm can go bankrupt. But several things had gone wrong because the animals aren't accurate farmers themselves. Otis milks himself wrinkly with the milk machine, Bessy and Abby refuse to use the milk machine on themselves, Pig eats all of the corn they picked (making him very fat), and Freddy goofs with the energy drink for the hens by putting dynamite in it, which he claims it is pepper, making the eggs the hens lay explode on contact.

A hedgehog named Don Bling convinces Otis to fight in a wrestling match but it turns out that all of the matches are fixed so then Otis' opponents all lose intentionally. Now, Abby, Pig and Pip must try to stop the hedgehog before Otis fights someone who is really trying.

When Duke tries crazy methods for the sheep to be safe during bear season, they escape and now Otis and Duke must go on a cross country trip to get them before they escape to New Zealand. Meanwhile, Abby and Bessy dress Pig, Freddy, and Peck as sheep. But it backfired when the farmer thought Pig had the "nervous woolies" when Pig accidentally said "Beeeee" and "Boooo" instead of "Baaaa".

After Mrs. Beady videotapes Otis and the gang walking and talking, she calls a news station to prove she isn't crazy with proof from the tape. The animals don't like it at all, though. Now, they try to interrupt the broadcast to not let any person see their everyday anthropomorphic behavior (and fulfill their dreams of becoming famous television stars). But it backfired, when the cameraman got a call from the network saying they're not on the air, leading the news station to change the animals' tv show back to the broadcast. So now the animals must now steal the tape to keep anyone from seeing their antics.

When the veterinarian stops by, she mentions that her van, the "Big Steer", won't last a week. However, Otis mistakenly thinks the veterinarian was referring to him and begins to think that he only has a week to live. To relieve himself, Otis tries to do everything he has ever dreamed of. When he returns, the animals are happy that he was gone so he abandons them. When he tried to do a jump over a canyon, he fell to the bottom and got injured. After that, the animals apologize to him for kicking him out of the barnyard.

This week's Moose Appreciation Week, so Otis disguises himself as a moose so he can get positive attention from humans, but his plan goes awry because the week is over and now the Moose HUNTING SEASON starts today and now Snotty Boy and his friends are trying to hunt him down, and his antlers are stuck to his head. So the animals rigged a robotic moose to scare Snotty Boy away from Otis. But Snotty Boy accidentally goes out on a busy road. So Otis has to save him from being hit by a car. Because of his heroism, the county now bans Moose Hunting Season and makes it Moose Appreciation Week all year long.

Upon realizing how lame his friends are: Freddy and Peck dressing him up as a bunny instead of a monster to scare away crows, Abby inviting him to bingo, and his friends habits at bingo (Pip's loud keyboard typing, Duke's squeaking his toy, Abby's slurping on a drink, and Pig digging in his ear), Otis ditches them and goes out for a night on the town, pulling pranks with the Jersey Cows. Otis, unfortunately, ends up getting arrested. So now his friends have to come get him out and stop the police officer from taking him away again.

Otis' favorite circus is coming to town, but the gang accidentally injures the main lead. Feeling guilty, Otis offers to take over and along with his friends, but Abby is too afraid to do her part because of an incident that happened long ago: She had dropped her partner when trying to catch him. Abby refuses to do the part because of being afraid to drop Otis. But without Abby, the show ends up being a disaster

After the gang notices a distinctive birthmark on Pig's backside, Pig starts to believe that he is related to the royal Pampered Pigs. After training Pig, he becomes snobbish to his fellow companions.

The animals become pop stars when Pip broadcasts one of their sessions, but soon their egos begin getting out of control and begins to put a damper on their friendship, which eventually causes a heartbroken Peck to quit.

Freddy tries to hide his non-carnivore ways from his parents, who are invited to a birthday party at the farm, and Freddy tries to make sure they don't eat anybody, including Peck, while keeping it a secret to his friends.