I LOVE my ratties! I have 10 adults and 4 litters due any day
I am just starting out breeding them (but I have been breeding mice for ~5 years). Rats make WONDERFUL pets...they're like little dogs that don't bite and like to snuggle....lol I definitely think the boys are more mellow on average...and I haven't noticed too much odor difference between my boys and girls (I have 5 of each and normally the boys are all in one cage and the girls are all in one cage.....except now with the girls being due they are separated into more). I feed almost exclusively Harlan Teklad 2018 lab block...though the girls that are pregant are getting some dog food as well (merrick before grain and taste of the wild mix). They all occasionally get veggie, "cereal," or fruit treats.
A converted bird cage can make a great cage for rats as long as you can give them solid surface shelves
Wire surfaces of any spacing frequently cause bumblefoot and are too be avoided in general. You can always cover shelves with cardboard or newspaper or the like.
In my experience a lot of rats won't use any wheels at all...but for those that will the only type I will use is a saucer wheel (
http://www.petdiscounters.com/Flying-Saucer-Exercise-Wheels-p8564.html)
Even rats from breeders frequently "carry" "myco" (short for mycoplasmosis)...many rats will never present symptoms...or will only be symptomatic in times of great stress. It cannot be cured...but antibiotics can repress it.
I agree with the comments about them being better than hamsters, gerbils, and g. pigs.....sooooooo much more social and interactive! Mice are better than all of them too...but I would put rats a little ahead of mice (I love my meecers as well!). You can train rats almost like dogs....and it is hard to get them to bite. I've worked with hundreds of each having worked in pet stores the past couple years...besides what I've owned and bred myself.....dwarf hamsters are demon spawn...syrians are slightly less evil, gerbils are just plain crazy, g. pigs just aren't very interactive....mice and rats very very very rarely will ever try to bite, and are very social, intelligent, and interactive!
You will have so much fun with your new boys!!! Enjoy them!!