lump on duck's back

[Blueberry780]

Blue, my one year old male jumbo pekin duck, has a lump on his back. It's bigger than the size of an egg, and it's causing him discomfort. He is struggling to get up and walk because he is doing a gagging motion. He is also nibbling on the lump. I checked under his feathers and i don't see anything external. I notice that the lump appears after he eats, maybe about 30 minutes later. I gave him some water, and massaged the lump, and the lump went down in size and he stopped gagging. The lump felt hard, like a cramped muscle? I just don't know if he had food stuck there but I don't think food would travel down his back... Also his neck is moving very weird, he's bending it so he looks like he has a rectangle head, like he has a forward head if that makes sense. When I touch his neck one bone feels off it just don't feel right. I don't think it's broken, I just don't know what it is if he has something stuck. Just to mention he has a slipped hock joint, so he already has trouble walking, but I carry him everywhere and I make sure his space is limited and he is close to food and water. I don't know if the lump could be connected to this. Also, since he is male he has a curled tail normally but I know they go through molt and they get a new one but blue has not gotten the curl back its been 3 weeks and no curl. His quack is still raspy though. Again idk if this is connected to the lump.
Sorry if i am overthinking this

also vet is not an option

(He is in a bucket because I bring my ducks inside at night since we are still reinforcing the coop)

 

[Chicken_Obsesser]

@shawluvsbirds @Jenbirdee @casportpony

 

[Jenbirdee]

I just fwdd ur msg to miss Lydia (duck educator here who can’t get online due to no Internet since hurricane Helene) I’ll let you know if she has any ideas. I’ve never seen or heard of that before.

 

[Blueberry780]

I just fwdd ur msg to miss Lydia (duck educator here who can’t get online due to no Internet since hurricane Helene) I’ll let you know if she has any ideas. I’ve never seen or heard of that before.

ok thank you! yeah i tried googling but there's nothing similar to this.

 

[Jenbirdee]

Miss Lydia said

Did she say how long he has had this? I really don't know what it could be since she said she massaged it and it went down in size. So doesn't sound like a tumor. I'm not sure if ducks get muscle spasms. Anyone else give any ideas?

 

[Blueberry780]

Miss Lydia said

Did she say how long he has had this? I really don't know what it could be since she said she massaged it and it went down in size. So doesn't sound like a tumor. I'm not sure if ducks get muscle spasms. Anyone else give any ideas?

I think it's been two weeks that he's been having this lump appear. I've never seen it on my other ducks, but i think it might be a muscle? I touched my other duck and he has it too but its not enlarged or bulging out like it is for blue. I was watching blue eat this time and he may be straining the muscle for some reason, but it's causing him to cough the food when he eats. I really don't know why it's happening. He's eating the proper food, I'm putting oregano and niacin supplement for him and he's eating from a duck feeder too. Google said they can have muscle spasms but it's due to sicknesses which blue isn't sick, he looks healthy and there's no other symptoms so I don't think that's the case.