What are some good sources of fiber? For Beaker.

Here is a good read...hope it helps! Dark green veggies look to be at the top of the list. http://exoticpets.about.com/cs/birds/a/ ... iets_2.htm

Plant based foods in general have a lot of fiber and that's mostly what birds eat, so he should be getting a lot already. I did some looking on the internet and came up with this:

Kale = 2% fiber
Carrots = 2.8% fiber
Raw dehulled millet = 8.5% fiber
Raw dehulled sunflower = 8.6% fiber

All those figures came from the same website (http://nutritiondata.self.com/) so presumably they calculated the percents the same way for everything. I have a scientific paper on the nutrient content of seed mixes and pellets which says that in general seed mixes are 3.7% fiber plus or minus 0.8% (after removing the hulls), and pellets are 3.7% fiber plus or minus 1.2%. These numbers are obviously a lot less than the first list, and I don't know which one is more accurate. But it looks like pellets have about the same amount of fiber as seeds do.

Is Beaker constipated? If so, it's possible that not drinking enough water is the real reason.

I think so. Just a bit. There's no poop stuck to his vent or anything, but sometimes it seems like he struggles a little. Perhaps I'll mist off the cage tomorrow. That's the only way I know to get them to drink more water. They like to lick it off the bars and preen their wet feathers.

What does fiber do? Help with weight gain?

Fiber isn't digestible but it provides bulk which helps keep food moving through the system. Humans who don't have enough fiber in the diet have a lot of problems with constipation. But it's usually not an issue with birds because their diet naturally contains a lot of fiber.

Ah okay.