BAT FILE NOT GIVING PROPER RETURN VALUE in TXT file

Hi All,
 
I am using below bat file which should return output text as URLs which are NOT browsable(eg. page not found error) but it is actually returning all successful ping in output text.Please help me to modify my bat file:-
 
@ECHO OFF
 
SET output=FaultyURLs.txt
 
IF EXIST "%output%" DEL "%output%"
 
FOR /f %%a IN (URLs.txt) DO (
 
CALL :ping %%a
 

 
)
 
GOTO :EOF
 

 
:ping
 
ping -n 1 %1 | find "Approximate round trip" >NUL || ECHO %1>>"%output%"
ECHO URLs SCANNING COMPLETED
ECHO
PAUSE>NUL