Our flex resistors are giving incorrect values - c++

Question

We are working on a Arduino project where we use different methods to change the power of three LED's making our own "RGB" lamp and the current issue is with flex resistors. The idea is to use three flex resistors to control each lamp. We used the map function with out lowest & highest value making our lowest number 0 and our highest 255.
The issue is primarily that our number fluctuate a lot and the laps flicker like crazy.
Any recommendations?
We've tried changing our mapped numbers, both max and min.
We've also played around with the code but with no success.
#include <LiquidCrystal.h>
int bend1 = A0;
int bend2 = A4;
int bend3 = A5;
int green = 6;
int red = 10;
int blue = 9;
unsigned long previous = 0;
const long interval = 500;
const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);
void setup() {
Serial.begin(9600);
Serial.println("Started");
lcd.begin(16,2);
pinMode(green, OUTPUT);
pinMode(red, OUTPUT);
pinMode(blue, OUTPUT);
}
void loop() {
unsigned long currentMillis = millis();
if (currentMillis - previous >= interval)
{
previous = currentMillis;
lcd.clear();
}
int value1 = analogRead(bend1);
int value2 = analogRead(bend2);
int value3 = analogRead(bend3);
value1 = map(value1, 510, 910, 0, 255);
value2 = map(value2, 490, 905, 0, 255);
value3 = map(value3, 500, 900, 0, 255);
if(value3 > 20)
{
analogWrite(blue, value3);
}
else
{
analogWrite(blue, 0);
}
if(value2 > 20)
{
analogWrite(red, value3);
}
else
{
analogWrite(red, 0);
}
if(value1 > 20)
{
analogWrite(green, value3);
}
else
{
analogWrite(green, 0);
}
lcd.setCursor(0, 0);
lcd.print("GREEN");
lcd.setCursor(7, 0);
lcd.print("RED");
lcd.setCursor(12, 0 );
lcd.print("BLUE");
lcd.setCursor(0, 1);
lcd.print(value1);
lcd.setCursor(7, 1);
lcd.print(value2);
lcd.setCursor(12, 1);
lcd.print(value3);
}
We should get the values 0,0,0 when all flex resistors are flat but instead they fluctuate from -10 ---> 90 in some cases. One of our fault might be faulty flex resistors. But we think there might be some code issues hidden also.