Yes, but unneccessarily complicated

Using the joy of x, your code can be shortened to:

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

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

@hash{@keys} = (0) x @keys;
print Dumper \%hash;
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Update:Note the parentheses around the zero. Without them you just get a string of zeros and the other values are undef. Also, you don't need scalar because the RHS of x is already in scalar context.