Weak chicks

[Harris14]

I have a mixed flock. Older girls and 4 month old chicks. Some of the chicks are really weak. If bumped they fall over and lay there. Feeding time they jump in with the crowd and eat. Always have water. I add electrolytes and vitamins to water once a weak. Poop is normal. No new chickens have been added. One of my chicks died this morning. I gave ivermectin on the neck for mites. Elderberries grow around here but idk if they eat them.
I need actual answers on what could be the possible causes and treatments.

 

[BDutch]

I don’t think anyone can give you answers without more info and seeing what the problem is.

What breed are the young pullets?
What kind of mites fo you have? Did you clean the coop throughly?

Ivermectin is poisonous and not allowed to use on chickens if you want to eat them/the eggs. Maybe you administered too much?

Elderberries are not poisonous for birds and chickens know what to eat and what not, if there is always healthy food available too.

It helps if you make a video of your chickens, post it on Youtube or Vimeo and share it here.

 

[coach723]

If you still have the one that died, or lose another, the best way to get an answer is usually necropsy.
Here are some resources by state, if you are in the US:
https://www.metzerfarms.com/poultry-labs.html
https://www.aphis.usda.gov/animal_health/nahln/downloads/all_nahln_lab_list.pdf

 

[Wyorp Rock]

I have a mixed flock. Older girls and 4 month old chicks. Some of the chicks are really weak. If bumped they fall over and lay there. Feeding time they jump in with the crowd and eat. Always have water. I add electrolytes and vitamins to water once a weak. Poop is normal. No new chickens have been added. One of my chicks died this morning. I gave ivermectin on the neck for mites. Elderberries grow around here but idk if they eat them.
I need actual answers on what could be the possible causes and treatments.

More info?
Photos of chicks, poop and housing? Thanks!

What do you feed?

You mention they are weak - have you eliminated the mites? Permethrin dust is an effective treatment if you dust the birds in 5-7 day intervals for several weeks.
While Ivermectin may help with Mites that bite the birds, you still need to treat housing and rid it of mites.
There's no once and done treatment for external parasites.

 

[Harris14]

Update: the chicks are doing better. I think it was prob the ivermectin.