I really don't know but they looked like some sort of bantam and I don't know if they'd be able to fly that far. The bank is about 10 metres from the island at its closest point.
A full-winged Peafowl would be able to make it off the island easily. Most chickens would probably end up in the water. Flight-restricted Galliforms are at risk of drowning, in proximity to steep-sided water of more than wading depth.
the owner told us that was where agressive roosters were taken to for the safety of visitors, the peacocks come and go as they please. We saw a yong deer splash thru the water to get to the island.