Online platforms are also a good option. Check e - book platforms or some reading apps. However, make sure the source is legal. For example, Amazon Kindle might have it if it's available in digital format.
Mang is definitely not a horse. There's no common reference or understanding that Mang represents a horse. Maybe you heard it wrongly or it's a made-up term in a very specific context that's not widely known.
I've never come across the term 'mang bts'. It could potentially be a nickname or a code word within a particular group or community, but without more context, it's hard to say for sure.
It depends on what you mean by healthy. If you're talking about the ingredients and cooking methods, some of their offerings might be considered healthier than others.