Nightmare tenant: unsanitary living, too many dogs

[Gabe N.]

Okay, so I have a couple that lives in my 4 plex that have been an absolute nightmare. So far they have consistently paid late and have been a nuisance with their dog (dogs) barking and making noise. They got on a one year lease in July a couple months before I purchased the property so they have 6 months to go now.

I am having the windows replaced and today the contractor got into their apartment (with proper 24 hours notice) and he found the place absolutely covered in dog urine and feces and instead of having one dog like they said they have 2 adult dogs, 2 puppies, and two cats living there unsupervised during the day and it's an absolute mess. It was bad enough that the contractor decided against using drop cloths on the floor since it would just soak up the multiple puddles of dog pee.

So I'm faced with a dilemma: do I give them a warning and have a frank conversation with them about their living conditions and possibly set up to inspect once a month to make sure it's staying fixed or do I head full steam towards evicting them? 

My major concern right now is that eviction would entail re-renting at a reduced rate since Alaska is in a bit of a recession, renovation costs right now, and renting during the winter is an issue. On the other hand if they stay they could still be doing damage but just cleaning up before inspection and if the dog mess is seeping through the laminate floor it could be damaging obviously the laminate but possibly even the subfloor which would cause a major cost in repair.

So, which route would you guys take?