Yes, you should clip one wing on each duck. This is for their own safety. I had mine fly to the neighbor's yard and not be able to get back over the fence. One ended up three houses down and I wouldn't have got her back except they knew I had ducks and called me. There are good videos on Youtube that show how to clip duck wings.
As for male vs. female, you have only two options. First is to learn to sex them when they are first hatched. This is difficult and takes practice but if you can learn it you will save money and probably be able to hire yourself out! The other option is to wait until their voices start changing at 3-4 months.
Unlike chickens, I don't think there is such thing as a sex-link duck that can be sexed at hatch by color. If there is, someone will brobaby jump in and tell us about it.
As for male vs. female, you have only two options. First is to learn to sex them when they are first hatched. This is difficult and takes practice but if you can learn it you will save money and probably be able to hire yourself out! The other option is to wait until their voices start changing at 3-4 months.
Unlike chickens, I don't think there is such thing as a sex-link duck that can be sexed at hatch by color. If there is, someone will brobaby jump in and tell us about it.