This is something I have been working on. I got thinking of modern Military Working Dog teams as I was preparing for an upcoming Only War campaign I am going to be running. When I was in Iraq, these dog teams were serious money makers, absolutely invaluable to the mission. For this specialty, I use the term "beast" to describe a wide variety of creatures that could be used across the Imperium.
Beast Handler
Characteristic Bonus: +5 Perception
Starting Aptitudes: Strength, Perception, Agility, Feildcraft, Defense, Social
Starting Skills: Awareness, Athletics or Dodge, Intimidate
Starting Talents: Weapon Training (Las or Solid Projectile, Low Tech), Double Team
Specialist Equipment: Obedience Collar and Remote, Beast Med Kit
Wounds: 9+1d5
Comrade Advances
The Beast Handler's Comrade is not a human being, but a mid sized beast. Some may take the form of large hunting dogs, a carnivorous lizard, or whatever is appropriate for the background of your unit. The beast cannot receive orders from the Sergeant or anyone else but the Handler, and there are not benefits from having the Commissar execute the beast (killing the beast defeats the purpose of deploying the Handler to begin with, and many units regard well bred and trained war beasts as more valuable than your average guardsman). Also Medicae tests performed on the beast without a Beast Med Kit are performed at -20. Obviously, the Beast cannot perform Ranged Volley actions.
Bomb Sniffer
Type: Order (Half Action)
Cost: 250
Effect: The Beast uses its keen sense of smell to detect hidden explosive devices. The Handler gains +20 on Awareness rolls to detect hidden traps. It is ultimately up to the GM to decide if enemy devices, particularly advanced xenos technology, is beyond the sensory capabilities of the animal.
Blood Hound
Type: Order (Half Action)
Cost: 200
Effect: The Beast is used to root out enemy ambushes, or to track down those who would evade the Emperor's wrath. The Handler gains +20 on Awareness checks to detect ambushes or track down enemies.
Scent of the Unnatural
Type: Order (Half Action)
Cost: 300
Effect: Beasts are often sensitive to the presence of warp. The handler may use this order to count as having the Psyniscience Skill.
Pack Hunter
Type: Passive
Cost: 200
Effect: The Beast and Handler have achieved an extremely close bond, being able to read each other in combat to devastating effect. The Character gains an additional +10 to his Melee attack rolls when the Beast is ordered into Close Quarters.