My approach was almost the same as yours except I used a function so I could short circuit and return as soon an item was determined to be missing.

use warnings;
use strict;
use Data::Dumper;

my @allwords = qw( mary had a little lamb its fleece was white as snow
+ );
my @checkwords = qw( little lamb fleece everywhere );

print "All words were ", check_array_for_words(\@allwords, \@checkword
+s) ? "" : "not ", "found.\n";

sub check_array_for_words {
    my ($ar_allwords, $ar_checkwords) = @_;
    
    my %hash;

    foreach (@$ar_allwords){
        $hash{$_} = undef;
    }
    print Dumper(\%hash);

    foreach (@$ar_checkwords) {
        if (not exists $hash{$_}) {
            return 0;
        }
    }
    return 1;
}

__END__
$VAR1 = {
          'had' => undef,
          'lamb' => undef,
          'a' => undef,
          'fleece' => undef,
          'little' => undef,
          'white' => undef,
          'as' => undef,
          'was' => undef,
          'mary' => undef,
          'snow' => undef,
          'its' => undef
        };
All words were not found.
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