by Pajarita » Thu Nov 02, 2017 11:11 am
Animals in captivity don't necessarily have to become fat. None of my birds is overweight (and none of my dogs or my cats, either] and I only ration their dinner [and that means that I give them enough to fill their crop and a little extra], never the food they get in the morning and left for them to continue eating, if they want to, during the day. Obesity is not only a matter of quantity of food, it's a matter of what food you feed and what exercise the bird gets as well as, believe it or not, how healthy the endocrine system is.
The thing about regurgitation is that, because birds have three stomachs [this is not really completely correct, I am simplifying it for the sake of the explanation], if the bird regurgitates all the time, no food is reaching is reaching the other two which are the ones that process the food for absorption in the intestines. When a bird swallows, the food goes into their crop, which is not a stomach per se but more like a pouch extension of the esophagus and where they 'store' the food and where the food gets moist and slightly softened by saliva, mucus and the heat of the body. The food in the crop then goes down to the proventriculus where it gets softened further and the 'breaking down' starts with the addition of gastric juices. Then it goes to the ventriculus, the more muscular of the three where the food becomes a homogeneous, soft mass called the 'chyme' and gets ready to go into the intestines and where the actual absorption of nutrients happens. When a bird regurgitates, it's bringing up food that is in the crop so, if the bird upchucks what is in the crop all the time, very little food will go into the proventriculus, the ventriculus and the intestines so I seriously doubt your bird is overweight. But this is actually very easy to check, all you have to do is weigh her regularly and see what kind of fluctuation there is.
I don't know why your bird regurgitates so much... I don't have a single bird that does it -well, some of them do regurgitate but they do it only during breeding season and only for their mates and they don't do it all the time, either. I'll be honest with you, if this was happening to one of my birds, I would be frantic with worry because this is a completely unnatural and harmful behavior. But I would never restrict food to a bird that has a medical issue like yours. I know that avian vets tend to say regurgitation is normal and it is! But not outside breeding season and not for only birds and not all the time. This never happens in nature so it's not natural and, if it's not natural, it's not 'normal'.
And I know that you said that she is kept at a solar schedule and that her diet is adequate but I still think that there is something not quite right with both or either one because the ONLY reason for a bird to regurgitate is sexual hormones and they are regulated by light and diet. I recently realized that the budgie hens were not coming out of condition because there were still getting a bit of light from a lamp in the street through the closed blinds. It was the merest light but, apparently, it was enough for them because once I started covering their cage, they started going out of condition.