Vary -N=nn to suit your bandwidth:

#! perl -slw
use strict;
use threads;
use Thread::Queue;
use LWP::Simple;

our $N ||= 10;

my $Q = new Thread::Queue;

my @pool = map async{
    print "$_ :", head( $_ ) ? 'ok' : 'not ok' while $_ = $Q->dequeue;
}, 1 .. $N;

while( <> ) {
    chomp;
    $Q->enqueue( $_ );
}

$Q->enqueue( (undef) x $N );

$_->join for @pool;

__END__
C:\test>headUrls.pl -N=20 urls.txt
http://www.shops-gifts.shopiwon.com/ :not ok
http://1ezbiz.leadsomatic.com  :ok
http://Indserve.com/kids :not ok
http://16066.profitmatic.com :ok
http://1-family.com/office/web/tp514/Boats.shtml :ok
http://1mboard.proboards28.com/index.cgi :ok
http://1plus-longdistance.com/domain/ :ok
http://1stopsquare.com/101xyron.html :ok
http://1world.leadsomatic.com :ok
http://1stphoenix.veretekk.com/index.html :ok
http://1stphoenix.veretekk.com :ok
http://1bernard.veremail.com/index.html :ok
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