Logan

You are missing some information. In order to get all the collars, you need to go to the Bulba anomaly first and loot the dead dog there, then go fight the pack - this way you get both. Fight the pack first, and the other collar goes away.

Also, make sure you kill the Bloodsucker, and take it's collar. When speaking to Hamster at the end of the mission, be sure to choose the dialogue option to tell him one of the collars was on a Bloodsucker - he will give you a pistol suppressor. So the max reward for this quest is 3k coupons and a Tactical Pistol Silencer for NATO weapons - which is hard to come by early-game, as well as the perfect condition AKM-74S you find on Nightingale's body: this sells for another 3k coupons! So your real reward is really 6k. Great boost for an early player.