Staple FoodsMice need a mixed diet in order to thrive, though a mouse's diet should consist largely of grains. Hay, millet, oats, buckwheat, and barley are GREAT and luckily included in large quantities in most mixes! Wheat is also okay given your mouse isn't allergic.
Seeds and nuts are also good, but be aware that like humans, some mice have allergies to peanuts and sunflower seeds. Generally, though, they won't, and mice just LOVE these. However, many seeds can be very heavy in fats (sunflower seeds particularly). A mouse's favorite seeds are often sunflower, pumpkin, and flax.
Corn generally should be avoided when buying or making a mix. They're just there to bulk up a mix, and while mice do like corn, it doesn't offer a lot of nutritional value, and they rather have a pumpkin or sunflower seed. A little corn is okay. Mice also enjoy popcorn, but make sure it's unsalted and only used as a treat.
Meat protein preferrably should be included in mouse diets too. Mice aren't herbivores, they're opportunistic omnivores! This protein can come from cooked meat, scrambled or hardboiled eggs, safe dog foods, and store-bought insects.
Mouse-specific mixes tend to unsuitable for mice, says Pet Mouse Fanciers, and if you're looking for a mix, parrot, hamster, and rat food will do just fine. Honestly, I wouldn't concern yourself too much with which mix to buy, as long as you're aware of what's harmful to mice and look out for it.
Mixes I recommend:
- Kaytee Fiesta Mouse & Rat Food - While Kaytee is a low-quality mix, it provides the nutrients mice need and very often is the only mix sold in stores, or is the highest quality mix sold in a store... I use Kaytee for the large part for this very reason; small mammal food of better quality is just very difficult to come by where I live. Kaytee has a bit too much crude protein, but for a hobbyist, it shouldn't be much of an issue.
- 3-D Cockatiel Food - What a lot of mouse owners, especially myself, run into is most places don't sell small mammal feed at all. Birds luckily have a similar diet, though it tends to be more seed-heavy. 3-D has a ton of sunflower seeds and too much crude fiber, but otherwise it's a perfectly fine blend. What's great about 3-D is that it includes egg! My mice, at least, prefer Kaytee Fiesta and Tropical Carnival.
- Brown's Tropical Carnival Gourmet Gerbil & Hamster Food - I love Tropical Carnival, and get it when I can! This is also a mix recommended by Pet Mouse Fanciers, so I can assure you it's top quality. It's hard to come by where I live, sadly, but it's the only mix PMF recommends that I can find here.
- Brown's Tropical Carnival Gourmet Mouse & Rat Food - A bit more crude protein, but it'll do.
TreatsHere are some fine treats you can give your mice every now and again! They absolutely aren't meant to be large parts of their diet, though, and some can be harmful to diabetic mice. Also ensure your mouse isn't allergic to any of these!
- Unsalted popcorn
- Safe dog foods
- Fruits + veggies, preferrably dry, ensure seeds are non-toxic to mice if they contain them
- Pasta + some breads
- Some cereals
- Yogurt drops
- Scrambled or hardboiled egg
- Store-bought insects
Food to AvoidThe following foods are toxic, toxic in high amounts, or generally unsafe for mice!
- Spicy food
- Apple seeds
- Almonds in high amounts
- Raw meats + eggs
- Wild-caught insects
- Raisins in high amounts
- Strawberry tops
- Cherry pits
- Diary in high amounts
- Red meat
- EXCLUSIVELY Oxbow mix- has been found to cause failure to thrive + death in mice
- Anything containing ethoxyquin
- Anything toxic to mammals in general Remember mice are the primary animal used in food and drug testing. While dosages in mice and humans are very similar, remember mice are smaller than you, and it takes less to harm or even kill them!
Naturally, avoid things with lots of sugar and/or salt. It's okay in moderation, as we need salts and sugars to live, but mice get enough of it in their food.
If you know it's bad for you, don't give it to them! Take note of your mice's allergies too.
"Picky" Eating + ScavengingMice with varied diets tend to leave food they dislike- normally hay pellets- in the bowl. It looks a lot like they're picky eaters, like humans who just eat unhealthy foods over the healthy ones. THIS IS NORMAL!
This doesn't mean they don't eat these foods! They still do, and they eat more of it than you think.
Mice will dig through their bowls looking for a food they like. This is called scavenging, and as mice are scavengers, this is a healthy and natural behavior. Studies have even shown this to be good for a mouse!
Mice will also often bury the food leftover in their bowl in bedding, also a normal behavior which combines nestbuilding, digging, and scavenging. This also forces them to scavenge for their food, even if all the food in the bowl is the same at that point.
If you want a mouse to eat the foods they don't like when they've left all of it in their bowl, just let it sit there for about 3 days or so, dependent on how much there is. Don't refill it. They'll eat it, and even if it doesn't seem like the quantity of the food is decreasing, know it is. Mice like eating more than we do.
Do Mice Like Cheese?Depends on the mouse.
Of course, it's not the only thing they eat, and hell, they'd much rather eat a sunflower seed than cheese!
Diary generally should be avoided in mice, but it's okay as a treat every now and again. But no, mice aren't terribly crazy for cheese. Actually, nearly all mice find peanut butter to be the best thing ever.
I'm really not sure why people latched onto "mice love cheese", when it's so evident they don't love it as much as other food. But I get asked this enough to address it.