One of my rats are somewhat smaller than the rest.

Question
I bought 3 female rats 1 albino and two hooded ones.
My one rat Elouisa is a hooded little bit smaller than the other two but she eats the most. Violet my other hooded one which is the biggest and the last one Missy follows along side her. I was just wondering why is Elouisa so much skinnier and smaller than the other two?

Answer
Keep food out at all times, for starters. Rats do not over eat and if food is always available, they will feel secure and not feel the need to hoard it as much or try to eat it right away with worry that they wont have any more if they dont. Rats that have food out at all times are more confident. You should be feeding them a well balanced diet of dry rat mix (low protein and low fat) or a good lab block such as what harlan teklad offers. Mazuri is high in protein but if its not the ONLY food source and they do not eat more than a block or two every day, Mazuri is acceptable in my book. Another great rat food is by Oxbow called regal rat and its a good kibble for adult rats over 4 months old. I usually buy that from the internet as well since its so hard to find unless you know of a dealer which is usually the Vets office.
I prefer following a recipe to make my own rat mix such as what I have on my personal website when it comes to their dry mix.  For the fresh foods I offer peas and cooked carrots and other veggies, keeping corn limited but not out of the picture totally. Rats LOVE peas, and its funny to note that there is not one rat that I know of that doesnt peel the outer casing of the pea off first, setting it aside, eating the inside part of the pea and going back for the skins later, if at all.  Its so odd they all seem to do this. Let me know if your rats do it too.   Also, keep in mind every rat is different. I have had some rats weigh 288 grams and others weighing 800 and 900 grams plus. Males are often larger than females but females can get hefty, too.  How old are the rats?