On the opposite side of the public gallery, Macdonald's father Kerry sat behind the dock.
In his closing address, defence lawyer Greg King said the case was not about allegations, but about evidence.
The Crown alleges Mr Guy was shot dead about 4.43am, but Mr King said four nearby residents had given "cold, hard evidence" they heard bangs or were woken about 5am.
The only contrary evidence was the "convoluted" testimony of Derek Sharp, who said high-tension power lines nearby had made his alarm clock 15 minutes fast - which a defence expert witness later said was impossible.
Macdonald was seen on the family farm about 5am so he could not have killed Mr Guy then, Mr King said.
The only witness who was awake at the time of the shots, Bonnie Fredriksson, heard three bangs in quick succession, while flatmate Mr Sharp was woken by the first bang and heard two more.
Mr King said if there were three shots, the murder weapon could not be the farm's double-barrel shotgun, which Macdonald allegedly used.
An expert firearms witness yesterday said it would take seven seconds to reload the gun after firing two shots.
Mr King said the Crown had ignored car tyre marks at the scene and the sighting of a mystery sedan on Aorangi Rd.
Doubts were also raised by other aspects of the police inquiry, including the theft of shotguns in the area, a string of local burglaries, and a man who smelled of alcohol and cigarettes who came looking for Mr Guy at his old home days before his death.
Mr King said all of those aspects raised enough doubt without even getting into the dynamics within the Guy family.
There was no doubt Macdonald and Mr Guy had problems in the past, but it was Mr Guy who had caused the animosity when the Macdonalds moved into the family home on the farm.
Mr King said his client had admitted the "dreadful, shameless, shameful" acts of vandalism and arson against Mr Guy's property.
But the acts were directed at property, not people, which made "a world of difference".
Mr King questioned why Macdonald would murder Mr Guy, knowing that his accomplice in his earlier crimes, Callum Boe, could link him to them.
He also asked why he would commit "blatant murder" instead of making it look like a farming accident.
"Why not push him under a tractor, under a wheel."
And Mr King questioned why Macdonald would "inflict an unsolved murder" on his wife, his four children, his two nephews and his in-laws.
"You wouldn't do it to your wife and kids."
In his closing address, Crown prosecutor Ben Vanderkolk told the jury Mr Guy's murder was planned and "intensely personal".
Macdonald had repeatedly voiced concerns about unfairness or inequality on the farm, and felt threatened when Mr Guy announced he wanted to inherit the family farm.
The issues on the farm had been sorted out, but were still alive in Macdonald's mind and never went away, he said.
When new and wild ideas for the farm were discussed days before Mr Guy's death, Macdonald "gets it into his head" to commit murder.
Mr Guy's murder came after what the Crown alleges was a series of "failed, intensifying efforts" to intimidate Scott and Kylee Guy off the farm.
Macdonald put "poisonous letters" in their mailbox, burned down an old farm house on their property and vandalised a new house being built there.
The attacks were personal and stemmed from a "deeply embedded bitterness".
Mr Vanderkolk said there were no witnesses to the murder, but the Crown did not have to prove every circumstance or coincidence in the case beyond reasonable doubt.
Strands of facts in combination could prove guilt, and the jury should not be "scared or frightened" of finding Macdonald guilty.
Mr Vanderkolk said there were coincidences in the case that could not be explained away.
Macdonald knew the timing of the farm's morning routine and knew when to close the gates to Mr Guy's driveway to trap him.
Mr Guy got out of his ute, opened the gates and was gunned down by his killer. All Macdonald had to do to get away with the murder was return to the farm undetected and make it appear he had just got up to do the milking, Mr Vanderkolk said.
Once he was back to the farm everything he did was "safe, normal or explicable" as part of the normal farm routine.
But Mr Vanderkolk said there were telling signs.
Macdonald had used the words "his face" - even though he had not been close enough to see Mr Guy's face from the police cordon - and twice said Mr Guy had been shot before police knew how he had died.
"He knew because he was the gunman. He knew because he had taken those two shots."
Mr King will finish his closing address before Justice Simon France and a jury of 11 tomorrow.
