diff --git a/README.md b/README.md
index 745527a..1e7cf81 100644
--- a/README.md
+++ b/README.md
@@ -72,6 +72,7 @@ Usage: ./bin/TPMCalculator -g GTF_file [-d BAM_files_directory|-i BAM_file]
         -q    Minimum MAPQ value to filter out reads. Default: 0. This value depends on the aligner MAPQ value.
         -o    Minimum overlap between a reads and a feature. Default: 8.
         -e    Extended output. This will include transcript level TPM values. Default: No.
+        -a    Print out all features with read counts equal to zero. Default: No.
 
 ## Description
 
diff --git a/doc/Gencode_v25_FPKM_HTSeq.png b/doc/Gencode_v25_FPKM_HTSeq.png
new file mode 100644
index 0000000..0e36fa5
Binary files /dev/null and b/doc/Gencode_v25_FPKM_HTSeq.png differ
diff --git a/doc/Gencode_v25_FPKM_featureCounts.png b/doc/Gencode_v25_FPKM_featureCounts.png
new file mode 100644
index 0000000..5614cf5
Binary files /dev/null and b/doc/Gencode_v25_FPKM_featureCounts.png differ
diff --git a/doc/Gencode_v25_TPMCalculator_RSeQC.png b/doc/Gencode_v25_TPMCalculator_RSeQC.png
new file mode 100644
index 0000000..1580b6d
Binary files /dev/null and b/doc/Gencode_v25_TPMCalculator_RSeQC.png differ
diff --git a/includes/GenomeFactory.h b/includes/GenomeFactory.h
index fbc14df..22cbe92 100644
--- a/includes/GenomeFactory.h
+++ b/includes/GenomeFactory.h
@@ -9,6 +9,7 @@
 #define GENOMEFACTORY_H
 
 #include <unordered_map>
+#include <deque>
 #include <set>
 #include <vector>
 #include <string>
@@ -1191,6 +1192,10 @@ namespace genome {
 
             return currentIso;
         }
+        
+        std::deque<std::string> getChrOrder() const {
+            return chrOrder;
+        }
 
         GeneMultiSetItr<T> findGeneUpperBound(std::string chrName, unsigned int start, unsigned int end) {
             GeneMultiSetItr<T> it;
@@ -1242,6 +1247,7 @@ namespace genome {
                         try {
                             setCurrentChr(fParser.getWords()[0]);
                         } catch (exceptions::NotFoundException ex) {
+                            chrOrder.push_back(fParser.getWords()[0]);
                             std::pair < ChromosomeUnMapItr<T>, bool> res = chromosomes.insert(std::make_pair(fParser.getWords()[0], std::make_shared<Chromosome < T >> (fParser.getWords()[0])));
                             if (!res.second) {
                                 std::cerr << "Error inserting new Chromosome" << std::endl;
@@ -1268,6 +1274,7 @@ namespace genome {
             }
         }
     private:
+        std::deque<std::string> chrOrder;
         ChromosomeUnMap<T> chromosomes;
         GeneIsoformUnMap<T> transcript2Chr;
         SPtrIsoform<T> currentIso;
diff --git a/includes/ReadFactory.h b/includes/ReadFactory.h
index 0f42efc..3d70b81 100644
--- a/includes/ReadFactory.h
+++ b/includes/ReadFactory.h
@@ -332,7 +332,7 @@ namespace ngs {
         int processBAMSAMFromDir(std::string dirName, bool onlyProperlyPaired, uint16_t minMAPQ, uint16_t minOverlap);
         int processReadsFromBAM(std::string bamFileName, std::string sampleName, bool onlyProperlyPaired, uint16_t minMAPQ, uint16_t minOverlap);
         std::vector<BamTools::CigarOp> processCigar(std::string cigar);
-        void printResults(bool singleFile, bool extendedOutput);
+        void printResults(bool singleFile, bool extendedOutput, bool all_feat);
         void printResultsMatrix(std::string output_name, std::vector<std::string> tpmColumns);
 
         void processReadAtGenomeLevel(std::string chrName, std::string sampleName, std::set < std::pair<unsigned int, unsigned int>, coordinateLessCMP> read_coords, uint16_t minOverlap);
diff --git a/src/ReadFactory.cpp b/src/ReadFactory.cpp
index f68197a..4a00909 100644
--- a/src/ReadFactory.cpp
+++ b/src/ReadFactory.cpp
@@ -445,10 +445,10 @@ int ReadFactory::processBAMSAMFromDir(std::string dirName, bool onlyProperlyPair
     return totalCount;
 }
 
-void ReadFactory::printResults(bool singleFile, bool extendedOutput) {
+void ReadFactory::printResults(bool singleFile, bool extendedOutput, bool all_feat) {
     int count = 0;
     string sampleFileName;
-    SPtrChromosomeNGS c;
+    Chromosome<ReadData> *c;
     SPtrGeneNGS g;
     SPtrIsoformNGS i;
     SPtrFeatureNGS f;
@@ -496,11 +496,11 @@ void ReadFactory::printResults(bool singleFile, bool extendedOutput) {
             exit(-1);
         }
 
-        for (auto cIt = genomeFactory.getChromosomes().begin(); cIt != genomeFactory.getChromosomes().end(); ++cIt) {
-            c = cIt->second;
+        for (string chr : getGenomeFactory().getChrOrder()) {
+            c = getGenomeFactory().findChromosome(chr);
             for (auto it = c->getGenes().begin(); it != c->getGenes().end(); ++it) {
                 g = *it;
-                if (g->isProcessed()) {
+                if (all_feat || g->isProcessed()) {
                     out_gene << g->getId()
                             << "\t" << c->getId()
                             << "\t" << g->getStart()
diff --git a/src/main.cpp b/src/main.cpp
index 630d3dd..29f183c 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -43,6 +43,7 @@ void print_usage(char *program_name, int exit_code) {
     cerr << "-q    Minimum MAPQ value to filter out reads. Default: 0. This value depends on the aligner MAPQ value.\n";
     cerr << "-o    Minimum overlap between a reads and a feature. Default: 8.\n";
     cerr << "-e    Extended output. This will include transcript level TPM values. Default: No.\n";
+    cerr << "-a    Print out all features with read counts equal to zero. Default: No.\n";
     cerr << "\n********************************************************************************\n";
     cerr << "\n                        Roberto Vera Alvarez, PhD\n";
     cerr << "                      Emails: veraalva@ncbi.nlm.nih.gov\n\n";
@@ -64,6 +65,7 @@ int main(int argc, char *argv[]) {
     bool onlyProperlyPaired = false;
     bool singleFile = false;
     bool extendedOutput = false;
+    bool all_feat = false;
     set<string>features = {"exon"};
     unordered_map<string, string> featuresToCreate = {
         {"exon", "intron"}
@@ -184,6 +186,8 @@ int main(int argc, char *argv[]) {
                 onlyProperlyPaired = true;
             } else if (option.compare(1, 1, "e") == 0) {
                 extendedOutput = true;
+            } else if (option.compare(1, 1, "a") == 0) {
+                all_feat = true;
             } else {
                 cerr << "Unsupported option: " << option << endl;
                 print_usage(argv[0], -1);
@@ -241,7 +245,7 @@ int main(int argc, char *argv[]) {
 
     cerr << "Printing results" << endl;
     fflush(NULL);
-    readFactory.printResults(singleFile, extendedOutput);
+    readFactory.printResults(singleFile, extendedOutput, all_feat);
 
     cerr << "Total time: " << uTime.getTotalTimeSec() << " seconds" << endl;
     return 0;