How to get non coding sequences

I have selected around 30 genes in rat genome (rn6). I would like to get the non coding regions (introns, downstream and upstream). I am used to pass through UCSC, define custom tracks, intersect with Ensembl, and send query to Galaxy. However, it seems that something is not working well. Indeed when the custom track contains 1 gene, I get around 220000 regions. When the custom track contains 30 genes, I also get around 220000 regions. It is not possible. Could you help, please.