I have three Welsh Harlequin ducks and one drake all about 9 months old. I got my first egg on January 12th and have been getting a egg a day sense. At nine months I would think they would all be producing eggs. they eat high protein flock raiser and get supervised free range almost daily. I have been told Welsh Harlequins are prolific layers but why would only one of my three be laying at this age?
I wouldnt worry. Its winter and they are not going to be at their peek in the winter. Give it another month or so. Plus if they just started their bodies are just getting situated. Also if you were getting an egg a day most likely different birds were laying on different days, in the begining they dont normally lay every single day.