Role in the film
Dag and five of his gang break into the henhouse and nearly steals a few of the hens, only to be stopped by Otis' foster father, Ben. He had sacrificed himself to save the hens and succumbed from his injuries after his fight with Dag.
Later, Otis tries to take vengeance on Dag, but he loses his burst of courage as soon as the coyotes noticed him. Dag sadistically shames Otis by telling him that things would have been different if he was there for Ben. He then makes a "deal" with Otis, telling him that he will only steal a few animals each night, but if Otis tried to do anything about it, Dag and his pack would slaughter every animal in sight, possibly including the farmer. In the morning, Otis decides to leave the barnyard, realizing that he has no chance.
However, the next morning, Otis was informed that the coyotes took all of the hens and his chick friend, Maddy, making Otis realize that Dag double-crossed him, since he wasn't expecting him and the coyotes until tonight. Otis then went off to the junkyard to rescue the chickens.
Otis arrives at the junkyard just in time to prevent Dag from devouring Maddy, but Dag's goons easily overpower him. Fortunately, Miles the mule, Pip the mouse, Freddie the ferret, Peck the rooster, Pig the pig, and the Jersey Cows arrive to help Otis and Dag's goons were easily defeated.
Eventually, Dag tries a sneak attack on Otis similarly to how he overpowered Ben, but Otis was warned by Peck, who successfully did a loud crow. Otis caught Dag by the throat, hit his head against a bus window and threatened to punch him, like his father did; but instead, Otis warns the evil coyote to never come back and he agrees. Otis then whacks Dag with a golf club, sending him flying far, far out into the distance while howling in pain.
Though he most likely survived, it is unknown what happened to Dag afterwards. He and the other coyotes possibly still live in the junkyard presumably found new hunting grounds.
Dag is an outright merciless, sadistic, murderous, greedy, hedonistic, ruthless, and arrogant coyote. However, unlike many villains, whereas they are motivated by greed or power, he and his coyotes only want food. Yet, it is important to note that while they steal hens on a regular basis, Dag remains notably thin, so much that anyone can see his ribcage. This could either be a medical condition or he only kills for fun.
He is also seemingly slanderous, egotistical, and manipulative, as Dag enjoys to torment his victims, which was shown at the hen house where he revealed to them he keeps the severed legs of his meals and threatens one of them. This also passes onto at the junkyard where he came close to devouring Maddy simply because she called him a "meaner". Otis was his archenemy and in turn Dag took great delight in saying that he should have helped his deceased father, Ben.
Throughout the film, Dag proves that he is not above underhanded and exploitative tactics to win a fight this was shown when he attacked both Ben and Otis in their legs when they were distracted by his coyotes. This also shows at the junkyard when he was planning to attack Otis from above the top of a bus. Dag is also known to be very abusive, insulting, and argumentative, describing both the cows as "fat".
If his back is against a wall, Dag can also be very cowardly and fearful whenever Ben and Otis threatened to punch him and he quivered, which made both cows spare him.