Here an alternative version:

same idea, but without splice() by using more perlish features like list-flattening and arrayslicing

my @chunk;
while ( ( @chunk[0..19] , @array ) = @array ) {
        print "@chunk\n";
}
[download]

but I think splice is better maintainable!

UPDATE: Indeed, real splices are better, see "Good" style for splicing arrays for details.