diff --git a/API.txt b/API.txt
index d16d8e3..3bf8bb8 100644
--- a/API.txt
+++ b/API.txt
@@ -4,6 +4,14 @@ Creatures MOB-Engine API
 creatures.register_mob(#Creature definition)
  -registers a mob at MOB-Engine; returns true when sucessfull
 
+creatures.register_alias(old_mob, new_mob) -- returns true if sucessfull
+ -registers an alias for other mob, e.g. from other mods or removed ones.
+	existent entities (MOBs), Spawners and Spawn Eggs are converted;
+	returns true when sucessfull
+    ^ old_mob: name as string, e.g. "creatures:oerrki"
+    ^ new_mob: name as string, e.g. "creatures:oerkki"
+    ^ example: creatures.register_alias("creatures:oerrki", "creatures:oerkki")
+
 creatures.rnd(chance_table)
  -returns a weighted random table element; chance_sum of table must be 1
     ^ example: creatures.rnd({elem1 = {chance = 0.7}, {elem2 = {chance = 0.3}})
diff --git a/chicken/README.txt b/chicken/README.txt
index 5c45ab7..25fb1f2 100644
--- a/chicken/README.txt
+++ b/chicken/README.txt
@@ -2,13 +2,14 @@ Chicken for Creatures MOB-Engine
 ================================
 Copyright (c) 2015-2016 BlockMen <blockmen2015@gmail.com>
 
-Version: 2.2
+Version: 2.3
 
 
 Adds chicken to Minetest (requires Creatures MOB-Engine).
 Chicken spawn on dirt and grass blocks, have 5 HP and are friendly. When killed or dying
 they drop meat, which can be eaten or cooked and probably some feathers. Also they drop 
-randomly eggs, which can be thrown to spawn new chicken or fried and eaten.
+randomly eggs, which can be thrown to spawn new chicken or fried and eaten. They appear
+with white or brown feathers.
 
 
 License:
diff --git a/chicken/init.lua b/chicken/init.lua
index 5e00e90..5874001 100644
--- a/chicken/init.lua
+++ b/chicken/init.lua
@@ -55,6 +55,12 @@ core.register_craftitem(":creatures:feather", {
 	inventory_image = "creatures_feather.png",
 })
 
+
+local colors = {
+	white = {chance = 0.7},
+	brown = {chance = 0.3}
+}
+
 local def = {
   -- general
   name = "creatures:chicken",
@@ -74,14 +80,14 @@ local def = {
     idle2 = {chance = 0.69, duration = 0.8},
     pick = {chance = 0.2, duration = 2},
     walk = {chance = 0.2, duration = 5.5, moving_speed = 0.7, update_yaw = 2},
-    panic = {moving_speed = 2.1},
+    panic = {moving_speed = 3.1, update_yaw = 0.8},
     lay_egg = {chance = 0.01, duration = 1},
   },
 
   model = {
     mesh = "creatures_chicken.b3d",
-    textures = {"creatures_chicken.png"},
-    collisionbox = {-0.25, -0.01, -0.3, 0.25, 0.45, 0.3},
+    textures = {"creatures_chicken_white.png"},
+    collisionbox = {-0.19, -0.01, -0.19, 0.19, 0.52, 0.19},
     rotation = 90.0,
     collide_with_objects = false,
     animations = {
@@ -126,6 +132,20 @@ local def = {
     {"creatures:feather", {min = 1, max = 2}, chance = 0.45},
   },
 
+  get_staticdata = function(self)
+  	return {
+  		feather_color = self.feather_color,
+  	}
+  end,
+
+  on_activate = function(self, staticdata)
+    if not self.feather_color then
+      self.feather_color = creatures.rnd(colors) or "white"
+    end
+    -- update feather color
+    self.object:set_properties({textures = {"creatures_chicken_" .. self.feather_color .. ".png"}})
+  end,
+
   on_step = function(self, dtime)
     if self.mode == "lay_egg" then
       dropEgg(self.object)
diff --git a/chicken/textures/creatures_chicken_brown.png b/chicken/textures/creatures_chicken_brown.png
new file mode 100644
index 0000000..529a4fd
Binary files /dev/null and b/chicken/textures/creatures_chicken_brown.png differ
diff --git a/chicken/textures/creatures_chicken_white.png b/chicken/textures/creatures_chicken_white.png
new file mode 100644
index 0000000..8301537
Binary files /dev/null and b/chicken/textures/creatures_chicken_white.png differ
diff --git a/creatures/common.lua b/creatures/common.lua
index 8c9983d..110e334 100644
--- a/creatures/common.lua
+++ b/creatures/common.lua
@@ -25,17 +25,25 @@ nullVec = {x = 0, y = 0, z = 0}
 DEGTORAD = math.pi / 180.0
 
 -- common functions
-function creatures.rnd(table, errval)
+function creatures.sumChances(tab)
+	local psum = 0
+	for s,w in pairs(tab) do
+		psum = psum + ((tonumber(w) or w.chance or 0))
+	end
+	return psum
+end
+
+function creatures.rnd(tab, errval)
 	if not errval then
 		errval = false
 	end
 
 	local res = 1000000000
 	local rn = math.random(0, res - 1)
-  local retval = nil
+	local retval = nil
 
 	local psum = 0
-	for s,w in pairs(table) do
+	for s,w in pairs(tab) do
 		psum = psum + ((tonumber(w) or w.chance or 0) * res)
 		if psum > rn then
 			retval = s
@@ -50,6 +58,10 @@ function throw_error(msg)
   core.log("error", "#Creatures: ERROR: " .. msg)
 end
 
+function throw_warning(msg)
+  core.log("warning", "#Creatures: WARNING: " .. msg)
+end
+
 function creatures.compare_pos(pos1, pos2)
   if not pos1 or not pos2 then
     return
@@ -64,8 +76,8 @@ function creatures.findTarget(search_obj, pos, radius, search_type, ignore_mob,
 	local player_near = false
 	local mobs = {}
 	for  _,obj in ipairs(core.get_objects_inside_radius(pos, radius)) do
-    if obj ~= search_obj then
-      if xray or core.line_of_sight(pos, obj:getpos()) == true then
+		if obj ~= search_obj then
+			if xray or core.line_of_sight(pos, obj:getpos()) == true then
 				local is_player = obj:is_player()
 				if is_player then
 					player_near = true
@@ -73,33 +85,33 @@ function creatures.findTarget(search_obj, pos, radius, search_type, ignore_mob,
 						return {}, true
 					end
 				end
-        local entity = obj:get_luaentity()
-        local isItem = (entity and entity.name == "__builtin:item") or false
-        local ignore = (entity and entity.mob_name == ignore_mob and search_type ~= "mates") or false
+				local entity = obj:get_luaentity()
+				local isItem = (entity and entity.name == "__builtin:item") or false
+				local ignore = (entity and entity.mob_name == ignore_mob and search_type ~= "mates") or false
 
-        if search_type == "all" then
-          if not isItem and not ignore then
-            table.insert(mobs, obj)
-          end
-        elseif search_type == "hostile" then
-          if not ignore and (entity and entity.hostile == true) or is_player then
-          table.insert(mobs, obj)
-          end
-        elseif search_type == "nonhostile" then
-          if entity and not entity.hostile and not isItem and not ignore then
-            table.insert(mobs, obj)
-          end
-        elseif search_type == "player" then
-          if is_player then
-            table.insert(mobs, obj)
-          end
-        elseif search_type == "mate" then
-          if not isItem and (entity and entity.mob_name == ignore_mob) then
-            table.insert(mobs, obj)
-          end
-        end
-      end
-    end --for
+				if search_type == "all" then
+					if not isItem and not ignore then
+						table.insert(mobs, obj)
+					end
+				elseif search_type == "hostile" then
+					if not ignore and (entity and entity.hostile == true) or is_player then
+						table.insert(mobs, obj)
+					end
+				elseif search_type == "nonhostile" then
+					if entity and not entity.hostile and not isItem and not ignore then
+						table.insert(mobs, obj)
+					end
+				elseif search_type == "player" then
+					if is_player then
+						table.insert(mobs, obj)
+					end
+				elseif search_type == "mate" then
+					if not isItem and (entity and entity.mob_name == ignore_mob) then
+						table.insert(mobs, obj)
+					end
+				end
+			end
+		end --for
 	end
 
 	return mobs,player_near
diff --git a/creatures/register.lua b/creatures/register.lua
index 212c65c..922e9dc 100644
--- a/creatures/register.lua
+++ b/creatures/register.lua
@@ -53,6 +53,18 @@ local function translate_def(def)
       --if name == "attack" then new_def.modes[name].chance = 0 end
     end
   end
+
+  -- Check if the modes have correct sum
+  local mode_chance_sum = creatures.sumChances(new_def.modes)
+  if mode_chance_sum > 1 then
+    throw_warning("Chance of modes too high for MOB: " .. def.name ..
+        ". Mode chances will be incorrect.")
+  elseif mode_chance_sum < 1 then
+    throw_warning("Chance of modes too low for MOB: " .. def.name ..
+        ". Filling up to correct mode chances.")
+    new_def.modes["_empty"] = {chance = 1 - mode_chance_sum, duration = 0}
+  end
+
   -- insert special mode "_run" which is used when in panic
   if def.stats.can_panic then
     if def.modes.walk then
@@ -578,3 +590,46 @@ function creatures.register_spawner(spawner_def)
 
   return true
 end
+
+local function register_alias_entity(old_mob, new_mob)
+  core.register_entity(":" .. old_mob, {
+    physical = false,
+    collisionbox = {0, 0, 0, 0, 0, 0},
+    visual = "sprite",
+    visual_size = {x = 0, y = 0},
+    textures = {"creatures_spawner.png"}, -- dummy texture
+    makes_footstep_sound = false,
+
+    on_activate = function(self)
+      local pos = self.object:getpos()
+      if pos then
+        core.add_entity(pos, new_mob)
+      end
+      if self.object then
+        self.object:remove()
+      end
+    end,
+  })
+end
+
+
+function creatures.register_alias(old_mob, new_mob) -- returns true if sucessfull
+  local def = core.registered_entities[new_mob]
+  if not def then
+    throw_error("No valid definition for given.")
+    return false
+  end
+
+  register_alias_entity(old_mob, new_mob)
+
+  if core.registered_nodes[new_mob .. "_spawner"] then
+    register_alias_entity(old_mob .. "_spawner_dummy", new_mob .. "_spawner_dummy")
+    core.register_alias(old_mob .. "_spawner", new_mob .. "_spawner")
+  end
+
+  if core.registered_items[new_mob .. "_spawn_egg"] then
+    core.register_alias(old_mob .. "_spawn_egg", new_mob .. "_spawn_egg")
+  end
+
+  return true
+end
diff --git a/ghost/init.lua b/ghost/init.lua
index c3ef546..9a1c3ba 100644
--- a/ghost/init.lua
+++ b/ghost/init.lua
@@ -45,7 +45,7 @@ local def = {
   model = {
     mesh = "creatures_ghost.b3d",
     textures = {"creatures_ghost.png"},
-    collisionbox = {-0.25, 0, -0.3, 0.25, 1.3, 0.3},
+    collisionbox = {-0.22, 0, -0.22, 0.22, 1.2, 0.22},
     rotation = -90.0,
     animations = {
       idle = {start = 0, stop = 80, speed = 15},
diff --git a/oerrki/LICENSE.txt b/oerkki/LICENSE.txt
similarity index 100%
rename from oerrki/LICENSE.txt
rename to oerkki/LICENSE.txt
diff --git a/oerrki/README.txt b/oerkki/README.txt
similarity index 76%
rename from oerrki/README.txt
rename to oerkki/README.txt
index 97c8147..648b7e1 100644
--- a/oerrki/README.txt
+++ b/oerkki/README.txt
@@ -1,12 +1,12 @@
-Oerrki for Creatures MOB-Engine
+Oerkki for Creatures MOB-Engine
 ===============================
 Copyright (c) 2016 BlockMen <blockmen2015@gmail.com>
 
 Version: 1.0 Beta
 
 
-Adds classic Minetest Ghost called "Oerrki". (requires Creatures MOB-Engine).
-Oerrki spawn only at night or in dark places and remain around 5 minutes in the world.
+Adds classic Minetest Ghost called "Oerkki". (requires Creatures MOB-Engine).
+Oerkki spawn only at night or in dark places and remain around 5 minutes in the world.
 Other than Ghosts or Zombies they don't die by sunlight.
 
 
diff --git a/oerrki/depends.txt b/oerkki/depends.txt
similarity index 69%
rename from oerrki/depends.txt
rename to oerkki/depends.txt
index acd6e5b..864a01d 100644
--- a/oerrki/depends.txt
+++ b/oerkki/depends.txt
@@ -1,3 +1,3 @@
 default
 creatures
-
+oerrki?
diff --git a/oerrki/init.lua b/oerkki/init.lua
similarity index 79%
rename from oerrki/init.lua
rename to oerkki/init.lua
index 1d62e24..293a9e0 100644
--- a/oerrki/init.lua
+++ b/oerkki/init.lua
@@ -1,4 +1,4 @@
---= Oerrki for Creatures MOB-Engine (cme) =--
+--= Oerkki for Creatures MOB-Engine (cme) =--
 -- Copyright (c) 2016 BlockMen <blockmen2015@gmail.com>
 --
 -- init.lua
@@ -21,7 +21,7 @@
 
 
 local def = {
-  name = "creatures:oerrki",
+  name = "creatures:oerkki",
   stats = {
     hp = 13,
     lifetime = 540, -- 9 Minutes
@@ -36,9 +36,9 @@ local def = {
   },
 
   model = {
-    mesh = "creatures_oerrki.b3d",
-    textures = {"creatures_oerrki.png"},
-    collisionbox = {-0.25, -0.01, -0.3, 0.25, 1.75, 0.3},
+    mesh = "creatures_oerkki.b3d",
+    textures = {"creatures_oerkki.png"},
+    collisionbox = {-0.22, -0.01, -0.22, 0.22, 1.65, 0.22},
     rotation = -90.0,
     animations = {
       idle = {start = 1, stop = 23, speed = 15},
@@ -50,12 +50,12 @@ local def = {
   },
 
   sounds = {
-      on_damage = {name = "creatures_oerrki_hit", gain = 1.0, distance = 10},
-      on_death = {name = "creatures_oerrki_hit", gain = 1.0, distance = 10},
+      on_damage = {name = "creatures_oerkki_hit", gain = 1.0, distance = 10},
+      on_death = {name = "creatures_oerkki_hit", gain = 1.0, distance = 10},
       swim = {name = "creatures_splash", gain = 1.0, distance = 10},
       random = {
-        idle = {name = "creatures_oerrki_idle", gain = 1.0, distance = 25},
-        attack = {name = "creatures_oerrki_attack", gain = 1.0, distance = 20},
+        idle = {name = "creatures_oerkki_idle", gain = 1.0, distance = 25},
+        attack = {name = "creatures_oerkki_attack", gain = 1.0, distance = 20},
       },
   },
 
@@ -93,12 +93,12 @@ local def = {
     height_limit = {min = -200, max = 50},
 
     spawn_egg = {
-      description = "Oerrki Spawn-Egg",
-      texture = "creatures_egg_oerrki.png",
+      description = "Oerkki Spawn-Egg",
+      texture = "creatures_egg_oerkki.png",
     },
 
     spawner = {
-      description = "Oerrki Spawner",
+      description = "Oerkki Spawner",
       range = 8,
       player_range = 20,
       number = 6,
@@ -108,3 +108,6 @@ local def = {
 }
 
 creatures.register_mob(def)
+
+-- Convert "Oerrki's" (caused by typo)
+creatures.register_alias("creatures:oerrki", "creatures:oerkki")
diff --git a/oerrki/models/creatures_oerrki.b3d b/oerkki/models/creatures_oerkki.b3d
similarity index 100%
rename from oerrki/models/creatures_oerrki.b3d
rename to oerkki/models/creatures_oerkki.b3d
diff --git a/oerrki/sounds/creatures_oerrki_attack.ogg b/oerkki/sounds/creatures_oerkki_attack.ogg
similarity index 100%
rename from oerrki/sounds/creatures_oerrki_attack.ogg
rename to oerkki/sounds/creatures_oerkki_attack.ogg
diff --git a/oerrki/sounds/creatures_oerrki_hit.1.ogg b/oerkki/sounds/creatures_oerkki_hit.1.ogg
similarity index 100%
rename from oerrki/sounds/creatures_oerrki_hit.1.ogg
rename to oerkki/sounds/creatures_oerkki_hit.1.ogg
diff --git a/oerrki/sounds/creatures_oerrki_hit.2.ogg b/oerkki/sounds/creatures_oerkki_hit.2.ogg
similarity index 100%
rename from oerrki/sounds/creatures_oerrki_hit.2.ogg
rename to oerkki/sounds/creatures_oerkki_hit.2.ogg
diff --git a/oerrki/sounds/creatures_oerrki_idle.1.ogg b/oerkki/sounds/creatures_oerkki_idle.1.ogg
similarity index 100%
rename from oerrki/sounds/creatures_oerrki_idle.1.ogg
rename to oerkki/sounds/creatures_oerkki_idle.1.ogg
diff --git a/oerrki/sounds/creatures_oerrki_idle.2.ogg b/oerkki/sounds/creatures_oerkki_idle.2.ogg
similarity index 100%
rename from oerrki/sounds/creatures_oerrki_idle.2.ogg
rename to oerkki/sounds/creatures_oerkki_idle.2.ogg
diff --git a/oerrki/textures/creatures_egg_oerrki.png b/oerkki/textures/creatures_egg_oerkki.png
similarity index 100%
rename from oerrki/textures/creatures_egg_oerrki.png
rename to oerkki/textures/creatures_egg_oerkki.png
diff --git a/oerrki/textures/creatures_oerrki.png b/oerkki/textures/creatures_oerkki.png
similarity index 100%
rename from oerrki/textures/creatures_oerrki.png
rename to oerkki/textures/creatures_oerkki.png
diff --git a/sheep/init.lua b/sheep/init.lua
index 2872b32..f692de9 100644
--- a/sheep/init.lua
+++ b/sheep/init.lua
@@ -60,7 +60,12 @@ end
 
 
 -- white, grey, brown, black (see wool colors as reference)
-local colors = {"white", "grey", "brown", "black"}
+local colors = {
+	white = {chance = 0.7},
+	grey = {chance = 0.1},
+	brown = {chance = 0.1},
+	black = {chance = 0.1}
+}
 
 local def = {
 	name = "creatures:sheep",
@@ -78,7 +83,7 @@ local def = {
 	model = {
 		mesh = "creatures_sheep.b3d",
 		textures = {"creatures_sheep.png^creatures_sheep_white.png"},
-		collisionbox = {-0.5, -0.01, -0.55, 0.5, 1.1, 0.55},
+		collisionbox = {-0.45, -0.01, -0.45, 0.45, 1.06, 0.45},
 		rotation = -90.0,
 		animations = {
 			idle = {start = 1, stop = 60, speed = 15},
@@ -164,7 +169,7 @@ local def = {
 		end
 
 		if not self.wool_color then
-			self.wool_color =  colors[math.random(1, #colors)]
+			self.wool_color = creatures.rnd(colors) or "white"
 		end
 		-- update fur
 		setColor(self)
diff --git a/zombie/init.lua b/zombie/init.lua
index 98a16ed..a9b462b 100644
--- a/zombie/init.lua
+++ b/zombie/init.lua
@@ -51,7 +51,7 @@ local def = {
   model = {
     mesh = "creatures_zombie.b3d",
     textures = {"creatures_zombie.png"},
-    collisionbox = {-0.25, -0.01, -0.3, 0.25, 1.75, 0.3},
+    collisionbox = {-0.25, -0.01, -0.25, 0.25, 1.65, 0.25},
     rotation = -90.0,
     animations = {
       idle = {start = 0, stop = 80, speed = 15},