But something was wrong. Seven of their horses circled in the distance, whinnying in distress and refusing to heed their call. The reason became all too apparent when Ms Beattie went to investigate.
In a far corner, Lutin, the family's favourite miniature stallion, lay motionless on the ground. A deep cut ran from the horse's throat, along his stomach, and down to his groin. Lutin had been disembowelled.
"I ran across the field to the hay barrel and there he was - just lying on the ground, completely empty," she told The Independent on Sunday last week. "Lutin had been opened up and gutted like a fish, but there was no blood, no insides, nothing. It was as if someone had taken him away, done this horrible thing and brought his body back."
As Ms Beattie vomited on the grass at the sight, she realised that she had been targeted by what French intelligence described as a cell of militant Breton nationalists active in the area. Her crime? Following a route trod by thousands of Britons each year in search of a better life in France.
It was not the first time she had been targeted. Two years after moving with her three children to Brittany, her Shetland pony was killed with a bolt gun, and the family's German shepherd was poisoned.
The situation has become so bad that Ms Beattie has been forced to buy a high-voltage Taser gun - as used by the British police - for self-protection. Her children - Chad, 13, Biannca, eight, and Talan, three - keep their bedroom lights on at night for fear of further attacks.
The English are flocking south in unprecedented numbers. More than 300,000 British citizens now live in France - a number that is growing rapidly - and 10 per cent of those are lured to Brittany by cheap rustic properties.
Like dozens of other Britons, the Beatties imagined they would be spending their days enjoying fine foods and a better way of life than any existence in London when they moved to the small village of St Dolay. But the Bretons have made one thing clear: "les rosbifs" should go home.
Other English-speaking expatriates in the area also claim they are being targeted by locals. For their part, the Bretons claim the Britons refuse to integrate, speak the language or contribute to the community - and that they are imagining things.
But Ms Beattie is a fluent French speaker and her children even regard themselves as more French than British. They say the latest attack has left them terrified. "The police around here are useless," said Ms Beattie. "Everyone just closes their eyes: they don't want to see what is happening.
"There are a lot of people around here who have got nothing. They were born here, bred here and they will die here," she added. "They don't like me because I'm different: I'm not from here, I arrived with a lot of horses, and I'm an English-speaking single mother."
Resentment is building across France as English house-buyers force property prices up. In the neighbouring village of Théhillac, Jane Harris, a 31-year-old from Hampton Court in Surrey, has a similar story to tell. Ms Harris moved to the area with her English boyfriend a year ago. Since then, she said, they have had two goats poisoned, their dog attacked and a number of quad bikes stolen.
"We've had a lot of problems with our neighbours, because they seem jealous of us," Ms Harris said. "Nobody wanted the land and so we bought it, but now it's a problem, because it's the English who have bought it."
Ms Harris claimed the locals turn off their electricity "eight or nine times a day", and recently, when her boyfriend was away on business, one farmer came up to her back door at night and fired a shotgun in an attempt to frighten her.
"It has been pretty severe, but it's just pure intimidation," Ms Harris said. "They're trying to drive us out, but it's not going to happen. Don't get me wrong; we've got some lovely French friends. It's just a small minority who are like this - and they've picked on the wrong people this time."
Further north, anti-British graffiti have appeared on walls around Bourbriac, leading to it being dubbed "the village of hate". Slogans such as "Brits out" have been scrawled on the walls of estate agents. And last year a public demonstration was mounted to protest against high house prices, but few observers were in any doubt that the real target was "les anglais". Back in St Dolay, a barman in Au Relais des Chasseurs bemoaned the latest symbol of the English invasion: a £2.5m luxury golf complex being built by a British company nearby. He then poured a glass of Kronenburg and declared that Ms Beattie had made up the story of the dead horse. Some of his regulars also muttered darkly about what they describe as the British "invasion". The complaints were common: the English are pushing up house prices, taking their jobs and putting additional strains on their health service.
Yves Bompoil, a local agricultural worker, was particularly vitriolic. "There's nothing good about the English," he said. "There are far too many English here, and it's annoying when they don't speak French. It's not about nastiness or racism, but because they don't integrate properly, and they mess up the local economy. They should go back to buying houses in Spain."
Another local resident, who did not wish to be named, said: "Brittany is very proud of its identity and I don't think people want that identity diluted. Part of the problem is the affluence of the British who come here: it's provocative for people who are living on the minimum wage or are unemployed - especially as the affluent British householders tend to be arrogant and noisy."
Even some of the Anglo-Saxon incomers admit there is a problem. "The first rule when you travel is to respect the country you're in, but a lot of British people aren't doing that at all," said Susie Cowley, 44, a former Vogue cover girl who has lived in the area for more than a decade. "They stay in their cliques and try to manufacture a little England. I just wish they'd make a bit more effort - and not organise things like curry Sundays."
For Deborah Beattie and her family, however, the problems remain more serious.
"Unless the law takes things in hand, someone will eventually get hurt - either a child or an adult," she said. "It really is like the Wild West out here."
Ms Beattie said she planned to move in the new year - but only as far as Théhillac. Then, she said, she would relaunch her riding business, Planète Cheval.
"Yes, I'm giving them the satisfaction of moving, but I'm not going far," Ms Beattie said. "I closed my business the first time because my kids were suffering. But I'm hard now, because I've had to be - otherwise I'd just break down and cry."Reuse content