Some of the animals, including a Shetland pony, were so lame they could hardly move around in a field at Hen Heads Farm at Kings Highway near Haslingden.
Julie Lee, 51, of Spittens Farm, Roundhill Road, Accrington, pleaded guilty to three offences under the Animal Welfare Act and was sentenced at Blackburn Magistrates’ Court following a prosecution by the RSPCA.
She received an 18-week prison term, but magistrates agreed to suspend her punishment for two years.
The RSPCA was alerted about the neglect of the horses and attended - with officers from the World Horse Welfare charity - at a large moorland field on October 12 last year.
They found four of the equines had overgrown hooves and a vet later confirmed they were suffering from lameness. Three were overweight and examination showed others had not received proper dental care.
Veterinary surgeon Suzanne Green was forced to put to sleep three of the horses - including the pony - at the farm to end their suffering.
The other three were taken to boarding accommodation, where another of the horses, a Bay Welsh mare, was euthanased three days later to alleviate her suffering.
In the view of the veterinary surgeon the owner had not met the needs of the horses as she had failed to provide adequate veterinary care, farrier treatment and dental care as well as treatment for thrush and a suitable diet.
The 12-year-old Shetland pony was in so much pain she could barely move.
Inspector Alison Fletcher said in a statement: “She had extremely overgrown hooves, with the front hooves curling upwards and over.
“The pony looked extremely uncomfortable in its standing position. Every little move appeared to leave the pony in agony and she was reluctant to move at all. It was obvious that she was in need of urgent veterinary attention.”
After she was put to sleep the pony was carried off the moor by the two RSPCA inspectors, the vet and the two charity workers.
X-rays of the animal’s limbs confirmed her hooves were severely overgrown and curled up and that she was chronically lame.
An appaloosa mare and a gelding, who both were suffering from overgrown hooves and were lame, were also put to sleep by the vet.
An examination of the Bay Welsh mare showed she had not received dental treatment “in a number of years”.
A fifth horse was suffering from overgrown hooves and dental problems, while a sixth horse also had not received proper dental treatment.
Magistrates said they agreed to suspend Lee’s prison term because of her previous good character and had given her a reduced sentence of 18 weeks because of her prompt guilty pleas.
The defendant was also told to complete 200 hours of unpaid work as well as 10 rehabilitation activity sessions while a deprivation order was made against her regarding the two surviving horses, who will soon be made available for rehoming.
Lee also has to pay court costs of £700 and a victim surcharge of £128.
Her ban means she will not be permitted to own horses and equines for life.