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

my %hash = ( 1 => 'a',
            2 => 'b',
            3 => 'c',
            4 => 'd' );

my $size = keys %hash;
print "Total keys are $size.\n";
my $numSplit = 2;
my $partSize = $size/$numSplit;
my @keys = keys %hash;
my @arrHash;
while(my @keys2 = splice @keys, 0, $partSize ) {
  my %hash1;
  @hash1{@keys2} = @hash{@keys2};
  push @arrHash, \%hash1;
}
print Dumper(\@arrHash);