diff --git a/engine/src/main/coffee/engine/core/turtle.coffee b/engine/src/main/coffee/engine/core/turtle.coffee
index 46aab12b9..87c62bbdb 100644
--- a/engine/src/main/coffee/engine/core/turtle.coffee
+++ b/engine/src/main/coffee/engine/core/turtle.coffee
@@ -337,6 +337,10 @@ module.exports =
     breedHere: (breedName) ->
       @getPatchHere().breedHere(breedName)
 
+    # (String) => Array[Turtle]
+    breedHereArray: (breedName) ->
+      @getPatchHere().breedHereArray(breedName)
+
     # (Number, String) => TurtleSet
     hatch: (n, breedName) ->
       num         = if n >= 0 then n else 0
diff --git a/engine/src/main/coffee/engine/prim-checks/agentset-checks.coffee b/engine/src/main/coffee/engine/prim-checks/agentset-checks.coffee
index 79995127c..6e0ed3bfc 100644
--- a/engine/src/main/coffee/engine/prim-checks/agentset-checks.coffee
+++ b/engine/src/main/coffee/engine/prim-checks/agentset-checks.coffee
@@ -83,14 +83,10 @@ class AgentSetChecks
 
   # (String, Patch | Turtle | PatchSet | TurtleSet) => AgentSet
   breedOn: (breedName, target) ->
-    if checks.isPatch(target)
-      @prims.breedOnPatch(breedName, target)
-    else if checks.isTurtle(target)
-      @prims.breedOnTurtle(breedName, target)
-    else if checks.isPatchSet(target)
-      @prims.breedOnPatchSet(breedName, target)
-    else if checks.isTurtleSet(target)
-      @prims.breedOnTurtleSet(breedName, target)
+    if checks.isAgentSet(target)
+      @prims.breedOnAgentSet(breedName, target)
+    else
+      @prims.breedOnAgent(breedName, target)
 
   # (AgentSet[T]) => Number
   count: (agentset) ->
diff --git a/engine/src/main/coffee/engine/prim/prims.coffee b/engine/src/main/coffee/engine/prim/prims.coffee
index 079023d91..aae06464c 100644
--- a/engine/src/main/coffee/engine/prim/prims.coffee
+++ b/engine/src/main/coffee/engine/prim/prims.coffee
@@ -38,26 +38,15 @@ module.exports =
     boom: ->
       throw exceptions.runtime("boom!", "boom")
 
-    # (String, Array[Patch]) -> TurtleSet
-    breedOn: (breedName, patches) ->
-      turtles = flatMap((p) -> p.breedHereArray(breedName))(patches)
+    # (String, Agent) -> TurtleSet
+    breedOnAgent: (breedName, agent) ->
+      turtles = agent.breedHereArray(breedName)
       new TurtleSet(turtles, @_world)
 
-    # (String, Patch) => TurtleSet
-    breedOnPatch: (breedName, patch) ->
-      @breedOn(breedName, [patch])
-
-    # (String, Turtle) => TurtleSet
-    breedOnTurtle: (breedName, turtle) ->
-      @breedOn(breedName, [turtle.getPatchHere()])
-
-    # (String, PatchSet) => TurtleSet
-    breedOnPatchSet: (breedName, patchSet) ->
-      @breedOn(breedName, patchSet.toArray())
-
-    # (String, TurtleSet) => TurtleSet
-    breedOnTurtleSet: (breedName, turtleSet) ->
-      @breedOn(breedName, map((t) -> t.getPatchHere())(turtleSet.iterator().toArray()))
+    # (String, AgentSet) -> TurtleSet
+    breedOnAgentSet: (breedName, agents) ->
+      turtles = flatMap((p) -> p.breedHereArray(breedName))(agents.toArray())
+      new TurtleSet(turtles, @_world)
 
     # (Any, String) => Boolean
     booleanCheck: (b, primName) ->