The sentence for burglary was handed down despite defence claims that the 22-year-old and his underage accomplice had only entered the property to retrieve a football.
Spanish daily Publico reported that the man, a teenager at the time of the crime, and his junior partner fell afoul of the law in December of 2009 after climbing over a wall in the municipality of Las Rozas, Madrid,.
They then "seized a hen" with "the intention of making a profit".
As the bird-burgling duo climbed back out onto the street with their poultry plunder, they were apprehended by local policemen who seized the animal and placed them under arrest.
In the verdict, the court agreed with the prosecution's argument that the crime was one of burglary, not theft, because the property connected to the courtyard in which the hen heist occurred was occupied.
This was contested by the defence who produced photographs in court, subsequently released to the press, which show the property in an apparent state of ruin and abandonment.
The defence argued that the neither the accused nor his accomplice, who was too young to be prosecuted, were seen inside the property by police.
In his testimony, the accused said that he was waiting for his friend to retrieve a football that had gone into the property.
He said the police arrived at the same time as the hen appeared on the scene .
The judge rejected this and said that the man had been caught red-handed.
A secondary line of defence — that the man had acted out of "starvation" and had intended to eat the bird — also failed to convince the judge.
The accused went on to describe the verdict as "ridiculous" and the sentence as "totally unfair".
He now plans to launch an appeal.
Burglary normally carries a sentence of two to five years in imprisonment.
In this case, though, the incident was considered attempted burglary because the police recovered the hen.
The penalty was therefore reduced to 12 months.
The defence claimed that the law was improperly applied and that if a crime was committed – something they deny – the maximum penalty should be a fine and six months in prison.
They also pointed out that in the case of the sentence being upheld at appeal, the man would be sent to jail some four years after committing the poultry offence.