English

''I can could eat a horse.'' If you have just heard it for the first time you will be shocked and think  just'' aaaw OMG what are you saying?" 

But this how native English speakers talk  talking '' I can could eat horse.'' It means that he is very hungry

Example:- i was working , I haven't eaten all day, now I can could eat a horse.

This is an idiom like 'It's raining cats and dogs' or 'You are barking up the wrong tree.'

I don't think it's so shocking, considering the fact that some people do eat horses. 

We would never say  "I was working , now I can eat a horse." rather "I'm so hungry, I could eat a horse. " 

English

''i can(could) eat a horse'' if you heard it for the first time you will be shocked and just'' aaaw OMG what are you saying (?)

But this how native (English) speaker talking '' i can (could) eat (a) horse'' it mean that he very hungry

Example:- i was working , now i can eat a horse