Not sure why are converting to/from int if you are just passing through
Can you post the sending Arduino code as well.
Looks like there is a delay() on the send side that causes Serial.readInt() to timeout and just return one char as a number
See my tutorial on Arduino Software Solutions for various ways to read a 'whole' line of text.
This posting has a complete Serial connection between two arduinos.
It uses JSON, but you can just send plain text.
This tutorial is an earlier version of the code (use the code referred to in the post), but it contains the circuits for connecting various Arduino boards