Inspectors from the charity and World Horse Welfare were called out to stock belonging to Miss Vardon that was being kept in a field by the A41 in Forton, Shrops, on 30 April.
The 76-year-old, who has bred horses for many years, told H&H she had placed the horses in the care of someone else, as her husband was gravely ill in hospital.
She said she had been shocked to find they were not being looked after.
An RSPCA spokesman said: “The officers spoke to the owner of the horses and a member of staff who was looking after these animals.
“Both individuals were given advice by the RSPCA and the owner is fully co-operating with the charity.
“The RSPCA inspector will be revisiting the location in the near future to recheck the animals’ condition.”
Miss Vardon said the horses were now back at her Meretown Stud in Newport and were putting on weight.
“This is very unfortunate – the horses have been with somebody else and came back in the most appalling condition,” she said.
“My husband [John Baxter] had two heart attacks and a quadruple bypass at the end of February.
“I have a reputation for welfare – this is most galling.”
Miss Vardon set up the National Foaling Bank, a service that puts owners of orphan foals in touch with those of mares that have lost their foals and offers advice, in 1965 and has overseen more than 8,000 fosterings.
She has received a royal warrant after helping with a number of royal foals and
the MBE for her services to the horseworld.
This news story was first published in the current issue of H&H (7 June 2012)