I used HISAT2 to align more RNAseq fastq files and then featureCounts to count my features. All my mRNA counts look as expected but I want to count rRNA as well, however, it is saying 0 counts for rRNA even though I did not do rRNA depletion. I really want to know my rRNA counts. I used hg19 as my reference genome. Is there something I can do so that featureCounts will count rRNA?