The green bottle fly is a type of blowfly. Green bottle flies live all over the world.
Green Bottle Fly (Lucilia sp.).
There are several species of blowflies know as green bottle, from the location where the pictures were taken and from the look of the animal I think it is of a Lucilia, species, although it seems to be almost impossible to tell which one.
Blowfly larvae eat dead animal tissue. Because they eat decaying tissue, and not healthy live flesh, they can be used to clear wounds.
Blowflies can lay their eggs into any decaying organic matter, including stuff in the sheeps’ fleece. Once the maggots hatch they can irritate the animal and and skin irritation can turn into wound where the maggots can feast resulting in weaking of the animal or even death. Blowfly strikes can become a major problem for livestock in some areas.
Further Readings:
Blowfly strike in sheep – prevention and treatments.
Beneficial, Medical use of Maggots.
Medical Maggots Treat As They Eat.
Medical Maggots™ (maggot therapy, maggot debridement therapy, MDT, biotherapy, biosurgery, biodebridement, larval therapy).