I think you're right in attributing this to a food change. Since you're pursuing a better nutritional regimen, I would suggest a pellet diet. There are far fewer health problems overall in bird on pellets and you don't have to worry about fortifying or adding anything.
A diet consisting mostly of pelleted food supplemented with fresh fruits, vegetables, grains and a good seed mix that does not include sunflower seeds, is your parrot’s best choice.
It’s not easy for some birds to make the conversion, but quite often that’s because their owner is too easily swayed by their demands and fear that the bird isn’t going to eat at all if they don’t get their junk food.
When I take in rescues, one of the most common problems is nutrition. The birds are either terribly underweight or obese. Changing their diet is often a matter of life or death and I haven’t lost anyone to date.
I’ll try every type of pellet out there, whether fruity or plain, spicy or a combination – just be sure to get the size & type appropriate for your individual bird.
Offer a pellet from your fingers as a treat (if your bird is used to taking treats from your fingers that is) and go ahead and try one yourself so the bird can see. I’m serious – try it yourself. Your bird shouldn’t be expected to eat anything that you wouldn’t eat yourself.
I’ve mixed pellets in with cereal too, especially a good, healthy, low sugar type. Try crushing them into an all natural yogurt or baby food of mixed vegetables, sweet potatoes, squash or the like. One of our macaws started to love them when she found them in with her blueberries and other cut up fruit.
I’ve found it’s not a good idea to mix the pellets in with the seeds, but be creative otherwise.
One warning is that if you mix the pellets in with anything wet or even make a ‘mush’ out of the pellets using plain water, a natural, low sugar fruit juice – you must remove the dish (must!) after an hour or two, tops. There’s too much chance for bacterial growth in wet foods and this only makes a problem worse.
While making the conversion you need to monitor your bird very carefully. I strongly suggest getting regular weights.
A gram scale is one of the best investments a bird owner can make since many illnesses are not noticed until pretty far along. With a regular weight monitoring, you’ll know when a weight loss (or gain) trend occurs and may be able to stave off serious problems by catching them early.
I weigh everyone every Saturday morning, right after a dropping. They’ve come to expect it and happily step up on the scale when it’s their turn.
For more ideas and options at conversion, take a look at these links. There are as many ‘right ways’ as there are individuals.
When it comes to the droppings:
All bird droppings are made up of three parts: Faeces (feces), the solid, central part which can vary in color depending on the food the bird eats.
Urates, the next layer of the ring, which can be cloudy-clear or with shades of white, yellows and greens, again depending on the foods eaten.
Urine is the clear liquid, usually outer layer of the ring. Depending on the amount of fruits and fluids the bird eats/drinks, this can be a significant part of the dropping.
Human companions to birds need to learn what’s normal for their bird. When the bird is healthy, acting fine and eating a well balanced diet, there’s a general look to the droppings that may vary depending on the time of day, but are usually similar looking.
If a bird eats beets one day, the droppings may look frighteningly reddish. Sometimes when the bird eats more dark leafy greens (or blueberries), the droppings can assume a nearly black hue.
When a bird is on a largely seed diet, the feces may be any shade of bright green; pelleted diets without added food colorings would produce a dull, brownish-green. If the bird is eating colored pellets, the droppings may reflect what colors are most often chosen.
Again, I believe what you're seeing is a temporary result of the new food, but yes, keep a close eye on it. If they persist at being unusually formed like this, it's well worth finding a vet who will at least check a sample you bring in (ideally, bring the bird too of course).
One day of abnormal droppings (usually appearing too loose or liquid) is not typically an emergency. As long as the bird is still eating, drinking and acting normally, there’s no change in vocalizations, there is no feather fluffing (looking bigger), staying at the bottom of the cage or excessive sleeping - sometimes a change in droppings is little more than something that will last a few hours and be fine.
You're doing a fine job - it's obvious you love this little guy!