The survey tested about 4,000 samples of whole chickens bought from UK retail outlets and independent stores.
In February, the FSA said contamination had increased since November, with every major retailer failing to meet targets to reduce the bug.
Campylobacter is the most common form of food poisoning in the UK.
Some 73% of fresh shop-bought chicken tested positive for food poisoning bug campylobacter, a year-long study by the Food Standards Agency (FSA) has found.