it sounds like you really care about your bird, because you are thinking now about how to PREVENT problems like egg laying. thats really great to read.
egg laying is a complicated thing. I've heard that one way to prevent it is to make sure their environment does not stimulate them hormonally. i.e. make sure there are no nestbox or similar enclosed spaces that the bird can go into. also, another way to prevent it is to avoid overcuddling the bird. i think others may have further advice for you regarding this as well, but those would be the two most major things i can think of for now.
alekha wrote:(alexandrine parakeet)she is almost baby, having no feathers on body. i observed they didn't handled prperly and got problems in wings.
that the alex is 12 years old, and has no feathers likely means that it has plucked its own feathers out, esp. considering that she was not cared for properly by her previous owner. when you mention that she has problems in her wings, do you mean that she can't fly? or have they been clipped (with the ends cut off, but half of the feather missing) ? if the wing feathers have not been damaged by the birds plucking, there is hope that she can fly again. please post again and explain the "problem in her wings" part in greater detail.
also, have you taken her to an avian vet? this is a vet who specializes in birds . the vet would also be able to let you know if the feather plucking is medically related or not. i think a vet visit is definitely important immediately if you havent already gone, esp. considering the birds bad care under the neighbor you got her from. it will help put your bird on the right track healthwise, and the vet can also give you further advice on how to prevent egglaying in the future.