Hi.
Looks like Mycoplasma to me...
Where are your new chickens from?
...Do you know if they were on antibiotics before bringing them in...?
I would put one tablespoon of Apple Cider Vinegar per liter of water in the chickens' waterer - for 24-36 hours.
(Being careful to NOT put Vinegar in...
Hi.
I have never heard about Mallard patterned Dutch Hookbill ducks... but solid coloured ones exist : I know of a person selling them in France - entirely Black, Blue, and Brown ducks... (and White, of course!)
Dark Dusky coloured ducks are born entirely black.
Here ...
Hi.
• Dad looks Snowy/Silver - don't know how you would call this colour...
...but here : https://shagbarkbantams.com/our-hatchery/call-ducks/call-duck-in-snowy/
• Mom is Emery Penciled.
Here are pictures of Penciled ducks ...
Hi.
A shame.
I would really have liked to see a picture of your duckling's dad...!
Your duckling is Mallard patterned.
...Colour looks to be Blue Fawn to me...
(Meaning : Blue phase Mallard.)
I have just searched pictures on the Internet to see if your duckling could be Pastel instead, but...
Hi!
Same.
I'm so grateful there are people who take the time to explain the different colours (names + genetic)...
I have learned a lot thanks to them, AND thanks to the Calculator : https://kippenjungle.nl/kruisingEend.html
But we still need more pictures to put images to colours.
I own a...
Hi.
Hmmmm... I have indeed read somewhere Lavender were TWO Blue alleles instead, and so, a lighter phase of Lilac...?
So, it is a bit confusing...
In case you would be interested to know... in France :
• what we usually call "Lavender" is, in fact, the Splash colour - so, NO Brown allele...
Hi.
Ah, ah! Never too late to learn!
I was so confused, when I found myself with this duckling... : I had never seen a Splash duckling, so I thought I had a (somewhat light) Snowy (Harlequin) coloured duckling...!!
From what I have learned : yes, they can.
In fact, your seller was...
Hi.
If you want to see Lilac coloured ducklings, go see this thread : Lilac Indian runner? Genetics.
And if you want to see what a Splash one look like...
...here is a Splash coloured Duclair duckling :
Duclair ducks are not Swedish ducks, but they are similar.
So, do compare your Swedish...
Hi!
Well... Blue Swedish ducks are not sexable by their juvenile plumage, so you would need to voice sex them.
How old are they?
And do you have pictures?
(Some boys' bill start to turn green really early, so if yours do, you can assume it is a drakelet.)
Hi.
They look like Runners, though Theodore seem thicker (neck) than she should be...
...Not even sure Alvin is purebred : she looks stubby (lower half) - kind of...?
Of course : they could look like it due to the pictures - hard to see!
Are "Premium ducks" supposed to be purebred? I am not...
Hi.
Are you sure your boy is a Rouen?
Could you post pictures of him, please; so we can see for ourselves if he really is a Rouen drake, and if he looks healthy?
Also, it would help if could answer some questions...
• What do you feed your drake, exactly?
• Has he an unlimited access to...
Hi.
You have two drakelets.
The vocal one - on our left - is clearly a boy : his voice is raspy.
The second one looks like a boy too : you can see his rump, like his brother's, is too dark for him to be a girl.
Hi!!
Ouch... I so hope Miss Nacho is hidden somewhere, sitting on eggs...
Huuuh...
Dad is : your Blue drake - he carries Brown in my opinion (I have made a lot of research since last year, so I'm going to trust what I have learned!).
Mom is : Miss Nacho.
It is just what I think, so don't...