diff --git a/data/sample.csv b/data/sample.csv
index c3be9f3..8483994 100644
--- a/data/sample.csv
+++ b/data/sample.csv
@@ -1,8 +1,8 @@
-id,birthdate,dam,sire,year,sex,weaning_weight
-1,1/1/1990,,,1990,male,354
-2,1/1/1990,,,1990,female,251
-3,1/1/1991,,1,1991,male,327
-4,1/1/1991,,1,1991,female,328
-5,1/1/1991,2,1,1991,male,301
-6,1/1/1991,2,,1991,female,270
-7,1/1/1992,,,1992,male,330
+id,birthdate,dam,sire,year,sex,species,weaning_weight
+1,1/1/1990,,,1990,male,cow,354
+2,1/1/1990,,,1990,female,cow,251
+3,1/1/1991,,1,1991,male,cow,327
+4,1/1/1991,,1,1991,female,cow,328
+5,1/1/1991,2,1,1991,male,cow,301
+6,1/1/1991,2,,1991,female,cow,270
+7,1/1/1992,,,1992,male,cow,330
diff --git a/gtktest.jl b/gtktest.jl
new file mode 100644
index 0000000..73396fb
--- /dev/null
+++ b/gtktest.jl
@@ -0,0 +1,13 @@
+using Gtk
+openpath = open_dialog_native(
+    "Select a datasheet")
+#     GtkNullContainer(),
+#     ("*.csv", GtkFileFilter("*.csv", name="Comma-separated values"))
+# )
+
+# savepath = save_dialog_native(
+#     "Save your results",
+#     GtkNullContainer(),
+#     (GtkFileFilter("*.txt", name="Results file"),
+#     "*.txt")
+# )
diff --git a/src/BeefBLUP.jl b/src/BeefBLUP.jl
index b06a5ae..4216ba8 100755
--- a/src/BeefBLUP.jl
+++ b/src/BeefBLUP.jl
@@ -18,7 +18,6 @@ using Gtk
 # Main entry-level function - acts just like the script
 function beefblup()
 
-### Prompt User
 # Ask for an input spreadsheet
 path = open_dialog_native(
     "Select a beefblup worksheet",
@@ -75,10 +74,7 @@ fixedfx = select(data, Not([:id, :birthdate, :sire, :dam]))[:,1:end-1]
 # Find any columns that need to be deleted
 for i in 1:ncol(fixedfx)
     if length(unique(fixedfx[:,i])) <= 1
-        colname = names(fixedfx)[i]
-        print("Column '")
-        print(colname)
-        print("' does not have any unique animals and will be removed from this analysis\n")
+        @warn string("column '", names(fixedfx[i]), "' does not have any unique animals and will be removed from this analysis")
         deletecols!(fixedfx,i)
     end
 end
@@ -92,9 +88,7 @@ end
 
 # If there are more groups than animals, then the analysis cannot continue
 if sum(numgroups) >= numanimals
-    println("There are more contemporary groups than animals. The analysis will
-    now abort.")
-    exit()
+    throw(ErrorException("there are more contemporary groups than animals"))
 end
 
 # Define a "normal" animal as one of the last in the groups, provided that