Hello,
My downstairs neighbor's apartment reeks of pet smell. They have dogs, birds etc in a very small apaartment. Since I have moved in there has been a really bad odor coming up through the drains in the bathroom. Can someone give me an idea on how to correct this? My thought is that they bathe the pets in the tub, and the hair gets clogged.

The past two days the drain has been pretty slow.

Thank you.

If the traps in your bathroom are full there would be no odor from downnstairs.
A more likely culprit would be rotting hair matted with grease that's making your drains smell bad. Try this for the drains that smell bad. Tonight before bedtine Take a 1/2 gallon of bleach and pour it down each drain and let set over night. Next morning ,(and this is important) flush out the drains with two large pans of boiling water to loosen the grease and flush the mess out. The bleach will make the hair slippery and began to dissolve it and the hot water will melt the grease and flush the mess away.
If the lavatory drain smells bad pull the stopper and look down the drain. There's a small rod sticking out in the drain that hair can build up on. Fish it out and then do the bleach thingy. Good luck, Tom

Do what Tom said. If it doesn't do the trick, chances are the smell isn't coming out of the drains. They may interconnect, but both yours and theirs have traps meant to stop gases and odors.

Instead, it may be coming up around the pipes. They need to caulked or foamed around. That will also reduce noise. It is really your landlord's place to take care of such stuff.