is my bird abt to lay an egg??

my friend gave me 2 sparrows to take care of for a month. one of the sparrow has started building nest.. n taking out materials from her toys to do the same.. it has turned abnormally big.. n has started loosing a lot of feathers too.. it keeps sleeping all day long with its neck hid inside her wings.. is it normal?? tell me what should i do??

I'm sorry I don't have answer to your question. My only suggestion is to try posting this question on another bird site or contact the wildlife rehab center and ask an expert.