Can a manly parakeet eliminate another manly parakeet?

And can it take a couple days for the victim to die? I heard one of the keets screaming and I go to him, and messed with him. At first he repeatedly bit me and hard. He ate hungrily on the seeds I dispense as treats (I give pellets in the cage). He seem alright afterwards. What was strange was he was letting me pet on him minus fussing and was even going to sleep on my finger, which I didn't think much of. Last night, he be on the floor of the cage and fluffed up. When I told my daughter my concern, we went to check on him, and he seemed fine consequently, moving around and eating like normal again. But he be hiding a couple times from out sight (Away from the other birds--all of the ones in this group were external the cage). This morning my daughter saw him and now says he looked healthy later, but later was crying out he was motionless, and I came but it was too late. We saw feathers contained by and out of the cage, like the kind you expect to see whether something had gotten him. This one parakeet had been stressed ample at one point to feather pluck, but I thought I had solved all that. These be still baby birds when I got them several months ago, but were shifting more recently. One was starting to get that brown shade on the cere. I have moved the cage just a couple days ago to what I thought was a better location to my daughter's room absent from fumes and such (because of the fireplace room door being opened, I didn't want them getting sick) but could it have be my daughter's sleep schedule (waking after 8 hours sleep), or the birds fighting? When I've been surrounded by pet stores, they don't seem to fight, but these were, particularly the 2 males.
I am just so disappointed and saddened by all this and feel terrible about it. Right now I have moved the parakeets to a different round up. None of them seem to be sick. And I am planning on throwing away some of their stuff, just within case. The other birds are not displaying any of the same behavior though as the one who passed.
Answers:    I'm sorry for your loss :(

Yes- Males can kill. But the flip side is- they generally do not. Male Parakeets are the more mellow bird, and it is the Females that are more agressive. However, it is possible that with your birds Cere that was turning brown (indicating a female to be precise going into her sexual maturity and able to breed- going into heat you may right to be heard?) that sometimes Males will fight over a Female that they wish to breed with- but once again, this is not normal.

Was your parakeet ALONE within the cage when it died? It is possible that it was still sick and was "play acting" robust. If it was alone, it may have been stressed out from self seperated from the pack (even at the risk of getting attacked- most birds would rather stay in it's "flock") and it is possbile that it pulled out feathers and then died from stress.

If it be in the cage with other birds, it may own been fatally attacked and then died. They can hold "frights" that give them heart attacks, and just like dying from "broken hearts", birds can also die from stress.

You will not involve to toss out all of the stuff from the other bird. Boil what you can (perches) and read up online about how to disinfect other toys (that cannot be boiled), and you will be able to set free most of the items (do not keep old treats and minreal blocks and such).

Sorry again!
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