(Reuters) - South Africa remains at risk of bird flu due to delays in the roll-out of a broad vaccination programme, the country's largest chicken producer, Astral Foods, said on Monday.

Last year, South Africa lost 9.5 million chickens, about a third of its national flock, during its worst outbreak of high-pathogenic avian influenza (HPAI), a bird flu with a high death rate that spreads rapidly through a flock.

The government has published guidelines for HPAI vaccination, but the poultry industry says the stringent biosecurity standards and monitoring protocols required are hindering vaccination efforts.

The South African Poultry Association says no company has met the requirements, despite eagerness to comply.

"Bird flu remains a major risk to the local poultry industry, with slow progress being made towards approval for the vaccination of broiler breeding stock," Astral Foods said in a statement.

South Africa's department of agriculture was not immediately available to comment.

Astral Foods posted 355 million rand ($19.56 million) profit in the six months to March 31, the first half of its financial year, up 472% from 62 million in the same period last year, when it suffered badly from power cuts.

The bird flu outbreak and the electricity crisis, blamed on South Africa's ageing coal-fired plants, cost Astral Foods 2 billion rand, pushing the company to its first ever loss of 512 million rand in the full year to Sept. 30, 2023.

The intensity of power cuts has eased during the past six months, a trend the government says is due to improved maintenance and a reduction in the number of breakdowns.

South Africa has now recorded more than 50 consecutive days without rationing electricity, the longest period of uninterrupted power supply in nearly three years, according to the official statistics agency. ($1 = 18.1448 rand)

(Reporting by Nelson Banya; Editing by Kevin Liffey)