Hello, is it normal for an analog input to still show very small random values even when using a pull-down resistor to prevent floating? I mostly see 0, but every second or so I'll see a value from 1-3. Thank you 
Sorry for making this post, I think this answers my question when it says "near zero volts"
BaconPizza:
Hello, is it normal for an analog input to still show very small random values even when using a pull-down resistor to prevent floating? I mostly see 0, but every second or so I'll see a value from 1-3. Thank you
That depends on the value of the pulldown and the amount of noise coupled capacitively to the pin.
Yes I'd expect that for 100k upwards if there's noise around. If there is a long trace on the pcb
or a long wire on the breadboard connected to the pin then 10k might show some counts too.
It's an 8:1 mux, since I'm not using Y4 - Y7 I've just put a 10K resistor from each one to ground. It's running on 5V. I was thinking it was possibly because of the resistors leads being exposed on the breadboard, since I haven't cut them to make them shorter.