Rats stink. And as your colony grows, so does the smell... I'm very sensitive to the smell, and being OCD, I obsess over it. There's no way to escape it when you live in a tiny apartment and have 3 breeding groups and grow outs in your bedroom. I've tried everything to control the odor and here are my thoughts. I am interested in your opinions and what seems to work best for you.

Food:
Quality food is important and greatly affects the smell. Higher protein content = stinkier rats! When I first began keeping rats I was feeding Kaytee Forti-Diet Pro (20% protein) and Mazuri Rodent Diet (23% protein). My rats would smell just hours after changing the bedding. Once I switched to Harlan 2018 (18% protein) there was noticeably less smell.

Heat:
The hotter it is, the stronger the odor.. I have no AC and get full sun, so I dread midday, but in the cool evenings I hardly smell anything. I can keep the room cool by creating a cross breeze through my apartment, which is very effective at suppressing odor... But I'm still looking forward to winter haha.

Baking Soda:
Baking soda can be used a few different ways. It can be placed in a bowl or open dish in the area of the rats, it can be sprinkled on the bottom of the rat enclosure and sprinkled into the bedding. I would not recommend mixing it in with the bedding as it can collect around the noses of pinkies and suffocate them. The method I found to work best was to line the bottom of the rat tub lightly, and add the bedding on top.

Vinegar:
Mixing half distilled white vinegar and half water in a spray bottle and applying to the bedding very effectively eliminates odor. However, it only seems to last for a day or so before the rat odor returns, and it makes the room smell like vinegar... When using this method, I recommend removing all rats and waiting 10 minutes before adding them back into the tub - the smell can bother their sensitive noses.

Vanilla Extract:
This method is effective in controlling odor, if added in the right amount. I use large 32oz water bottles for my rats and found that I needed to add enough to very faintly tint the water in order to see the results. However, for me it was not cost effective to add vanilla extract for all my rats each time I changed the water bottles, so I only use it for my larger groups. Make sure you are using Pure Vanilla Extract, and not imitation.

Bedding:
I experimented with many different types of bedding.. For the best odor control, make sure the bedding is deep enough. I provide my rats with 2-3 inches of bedding. Change the bedding often, once a week minimum. I often change the bedding twice a week, if I don't have the time to do a complete change, adding a layer of fresh bedding to the existing bedding can really help freshen up till the tubs can be changed completely.
Of all the types of bedding I tried (carefresh, aspen, yesterday's news, soil, eco earth, pine) the one I kept going back to was pine. Kiln dried pine is safe for rats and controlled odor the most effectively. Pine pellets - which can be found a local feed stores, is, in my opinion, the best method of odor control. However I personally choose not to use it with my rats because it does not seem very comfortable for them. Additionally, the dust can be dangerous to babies and cause suffocation so it should not be used with nursing mothers. I use a very finely shredded pine, and get great odor control. When buying pine, I definitely recommend checking out a local feed store. I was able to purchase a compressed 40lb bag for $6.25!

Odor Eliminators:
I have only tried one brand so far - Nature's Miracle Cage Odor Eliminator - which I found at my local Petco. This product does work and last roughly a few days. The best part, is that it is odorless and will not make the room smell or irritated the rats respiratory system. Fabreeze and similar products are great to have around as well.

Air Filters:
Being a poor college student, buying a carbon air filter is not possible, however I came across a simple DIY version using a box fan and HEPA filter. http://ball-pythons.net/forums/showt...r-for-about-25 I have not personally tried this yet but I have read reviews claiming it's effectiveness.

In short, the most effective methods for controlling odor - especially when breeding in a small apartment room like I do, is to, crack a window, turn on a fan, and change the bedding often. I love my rats and enjoy breeding them, but I'm obsessed with their smell and trying to minimize it.

Your thoughts?