How to read analog pins from a second Arduino
Yes that is possible, you can even use as many Arduino's as you want and send the information to one 'master' Arduino to process the data.

What you need is a way to communicate between them. Depending on distance, speed and reliability, you can chose for Serial, I2C, SPI or more 'exotic' solutions like CAN(bus), RS485 or even wireless methods (with nRF modules).

Some have a simple protocol, for others you might have to make it yourself.

Also think of the processing, you want to do the processing on the main device, or to process as much as possible on the 'slave' Arduinos and send it to the main device.

(Btw, I talk about Master/Slaves), these are not official terms, but meant as example. For example, with CAN, you can send message from any Arduino to any other. With Serial, you can send from 1 Arduino to 1 other.

If you have 2 Arduino's, probably Serial is the easiest.