Just need to point out that the translation is quite awkward.
It sounds something like
“There are thirteen dogs here that are colored red”.
A proper criminal gang name might sound like this
14 Red Dog Sect.
Often times 幫 (sect) is too obviously a gang name, so officially Chinese gangs would use the word 黨 (Society) publicly when filling out forms.
14 Red Dog Society.
For just 14 Red Dogs use,
14 Red Dog
You don’t have plurals. It’s contextual. You never point out that there are plurals if its in the context of a title.
edit* should probably add that 十四紅狗 alone sounds a bit weird in certain contexts. If you had a sign of sorts it would probably include 幫 or 黨. However if you had graffiti, 十四紅狗 doesn’t sound that weird. I dunno it’s hard to explain.