As stated it is very difficult to come across any kind of breeding pair, if you do you will be very lucky....
People buy juvis as a group and grow them up and wait for them to pair off, this is what we do to establish a breeding pair, so if you come across a true breeding pair ask to see proof, either with pics or documentation, Ie i will be selling my breeding pair soonish but exspect to pay more for proven pairs as all the hard work has already been done