This may be the 'Blackheaded pasture cockchafer', Acrossidius tasmaniae, which is a native pasture pest. Confirmation would require close examination of specimens.
Thanks, very much, Kim. Now that it’s been confirmed, do you have any advice re leaving them or giving the chooks a feed? Are they a fried or a foe to a conservation area?
Lisa, they are not a serious foe, so I would leave them. If they are indeed a native species, then they are part of the landscape and environment. Any damage they cause will be minor.