One horse at the J4S Equine Nursery has had an elevated temperature over the last two days.
Any horses returning a positive test will be euthanized.
The Queensland Biosecurity operation began on Saturday after the death of a five-year-old Anglo-Arab filly, Jackowahs Regal Princess.
However, two horses had died at the property in the preceding fortnight and it has yet to be determined whether Hendra was involved.
Two staff were sprayed with blood and mucus from the dying animal on Saturday.
Thirteen people have been tested for the virus but test results are unlikely to reliable so early in the virus's incubation period.
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