Crawl-delay: 10 or 5 which one should i put in robots.txt

Personally I don't bother with it at all. Googlebot doesn't support the crawl-delay directive, so for them it's pointless, and unless your site is getting hammered by a bot that a) supports crawl-delay, and b) respects robots.txt (which is a minority these days), there's no real benefit.

Why you want to delay it? It doesn't matter.