where do i find hays?

Those purple rhinodrakes are around lvl20; if your char is a lot lower levelled than that, the turtles in the river around lost city drop them too, but the drop rate is very low.

and where are these antelope-like things?

hay can drop of any kind of mob i got them from different mobs but drop rate is sooooo low

http://www.pwdatabase.com/pwi/items/9757

Try this one. Unless you've been to the site before, it'll send you to the MY-EN version of the page.