How can you make them have eggs?

Question

how can you make goldfish have eggs?

Answer 1

You mean birds?  You can't force them to lay eggs.

Answer 2

You can't MAKE them have eggs.  There are alot of factors that need to be considered and studied before attempting to breed birds.  One of the first things would be to figure out what kind of birds you have?  Are they are true pair...you will probably have to get them dna or feather tested to find out.  Then you need to study breed specifics.  Birds aren't like dogs or cats that pump out babies with any old dog.  They have a bonding process that they must go through and sometimes it may take months even years or never.  There is no way for anyone to answer this question for you.  They would have to buy a book.  google the type of birds y ou have and start there.