While I did manage much closer photos I still love to have the environment in an image. I think it gives some perspective to the story.
There is a large fresh water source in those woods.

Looking at the ponies you may see their stomachs are larger, more distended, than you might expect.
They graze and live on thick rough plants growing in brackish, salt water. These ponies drink more fresh water than any other horses due to this hard diet. Other breeds of horses introduced on the islands in the past did not survive in these conditions.
Hey Ted, any idea how old these animals get over there? I see some are from 2023, but are there any older ones around too?
Yes, not all are branded. Branding has to do with history, has someone purchased one as a foal but paid to keep it with them herd. All kinds of things.
I believe the palomino stallion here is 20 years old. Because the ponies on this island get year round vet care, and are monitored, they live 20+ years. If life gets too rough for some there are local farms that take them in.