Help! Suddenly lame ducks!

I have no clue what's happening and I'm in a panic. This morning one of my boys suddenly started collapsing. I brought him in and I've given him Vegimite water and peas. He can stand but is shaky but still can't walk and now one of my girls is finding it hard to walk and move. It's like they try but their legs just won't carry them. I've tried finding a vet but no one will look at them. They are both 2 years old. There is no stagnate water source in the yard, their bedding is clean and their pool gets fresh water in it everyday. I have 3 more ducks and 4 chickens and I'm worried they will all start dropping. What is going on?

That's terrifying!

I'm thinking that since it's summer there, they probably don't have any access to anything really moldy/very fungal? I had some die a few years back from what was probably fungal spores from a big load of wood chips.

I honestly have no idea what might be wrong, but hopefully someone else can chime in!

Also, maybe try adding a bit of apple cider vinegar to their water (something like a tbsp to gallon of water)? It can't hurt, and maybe it can help?

Nothing moldy I can find. The only thing that maybe moldy is the kitchen scraps they get sometimes.

Have they gotten any new types of kitchen scraps recently? I know some aren't good for ducks, and not all ducks are smart enough to avoid the things they shouldn't eat.

Pocket lettuce, bacon and carrots like 2 weeks ago.

We have not had ducks for years but did lose one some with similar symptoms to what you describe and what tested as botulism.  My husband remembers that it was some chickens and other ducks also...and the duck I'm remembering (Trucker the Duck) was sent to the lab...through the county extension agent maybe?...forty years ago now.

Here's a link describing it... https://nt.gov.au/__data/assets/pdf_file/0010/233569/botulism-in-chickens-ducks-and-others.pdf

Symptoms of botulism
Usually affected birds are found sitting or lying on the ground, hunched over and unable to stand. They are floppy and weak, and cannot hold their heads up. Sometimes birds may just be found dead, with no evidence of struggling. There is no diarrhoea or nasal discharge and no signs of injury. Often several birds in a group are affected at the same time, particularly the largest and healthiest. This reflects the feeding habit of the birds, which tend to congregate and peck at something they find interesting, with the smallest birds being pushed away.

What causes botulism?
Botulism occurs when birds eat food or drink water containing botulism toxin. The toxin is produced by bacteria called Clostridium botulinum. These bacteria are commonly found in the soil, and thrive in rotting vegetation, food or carcasses, where they produce a very potent toxin.  The toxin is also taken up and concentrated in maggots. The consumed toxin acts on the nervous system, causing weakness and paralysis. Botulism tends to be more common in the wet season, because birds are more likely to have access to wet, decomposing feed. Examples of situations where botulism can occur include birds pecking at rotten food scraps or the body of a dead bird or small animal (such as a dead mouse), or when the water level of dam or pond drops and the vegetation around the edge dies off and rots.  

See that's what I was thinking but I can't find anything that's been contaminated! It's baffling. Could it be from my lemons?

Scary!  If it's an obscure viral infection it is unlikely to spread to another species.  If it's environmental, it may spread.  What % protein are they on?  I know when turkeys don't get enough protein their legs start going lame and they will die if not boosted ASAP.

What are you feeding them? Vitamin deficiencies might be at the root of lameness or neurological malfunction. I know that ducklings need high levels of fat-soluble vitamins (A,D and E, particularly D) or they can get "rubber legs" and cannot walk or swim. The best sources for these vitamins is live food -- insects and other crawlies, slugs and snails. You may want to get some vitamin drops from the pet store and add those to the feed for a while.

Did you check their feet for cuts or bumblefoot? I've seen ducks go off their feet seemingly suddenly over such before.

I'd encourage swimming the next few days and give the two lame birds a safe space to rest.

What's their diet like? Do you supplement forage with a balanced feed? scratch or single grain rations? Etc.

Hopefully they'll come around over the next few days.

One other possibility is predator birds attacking from above?  I have seen chickens and ducks have their back injured from diving predators..