Working donkeys will have to be given a lunch-break
Some overweight children could miss out on seaside donkey rides under a new code banning riders over eight stone.
It also says donkeys must have at least one day off a week and a daily hour-long break in the early afternoon.
The code, drawn up by the British Equine Veterinary Association (Beva) and the Donkey Sanctuary, is voluntary.
However, owners who break it risk an improvement notice and subsequent prosecution under the Animal Welfare Act if action is not taken.
There are more than 900 working donkeys in the UK. The largest number, approximately 200, are in Blackpool.
Chris House, president-elect of Beva, says few owners are grossly negligent, but there is a fair amount of inadequate care.
The code will also request the animals are given decent housing and saddles which fit properly.
If the authorities find the code has been breached they can issue an improvement notice.
If the owner fails to improve care of the donkey, they could risk prosecution under the Animal Welfare Act for not upholding their duty of care for the animal.
Karen Richardson owns 15 donkeys on Blackpool beach, her family have been in the business for four generations.
She says the hardest bit of the code to adhere to will be the weight restriction.
"If a family come down with four or five children, how can you say that one of them can't go on? It might be the middle one who's overweight - very awkward situation," she said.
She says the number of larger children wanting rides has gone up noticeably over the years.
"Kids are a bit more overweight than usual for their age, but you don't walk around with scales and say, 'Step on them'," Ms Richardson added.
Some local authorities, including Blackpool, currently have their own guidelines governing the treatment of donkeys.
And under UK law, all working donkeys must undergo an annual veterinary inspection - a bit like a donkey version of a car MOT - and be signed off as fit to work by a vet before the season starts.
Donkeys that pass the inspection either have their hooves branded with a number, or a microchip fitted so any unscrupulous owners cannot swap or re-name them.
The code aims to bring in a UK-wide standard of care. Vets who carry out the donkey "MOTs" have agreed to incorporate the requirements of the code into their tests.
At the moment, there is no legal requirement for owners to be inspected once the annual donkey "MOTs" have been carried out. The authorities mainly rely on members of the public or volunteers alerting them to cases of abuse.
Chris House, of Beva, hopes this may change if and when Defra brings in an equine code of practice.
"An equine code of practice would be much more powerful, it's government legislation. It would require welfare inspectors to be appointed to endorse it," he said.
The Animal Welfare Act allows for the creation of a specific equine act. Defra is currently considering whether or not this should be a legislative priority.