Cocci in 5 day old?

[TLWR]

I have lost 2 chicks in the last few days.
Chick1 and 2 were brought home Saturday. Chick1 hatched that day. Chick2 probably day before.
Brooder is Dane sized kennel on my patio. Using towels and changed daily. Using medicated feed.
Chick 1 and 2 were in yard for a short bit on Saturday and probably Sunday as well. Then back to brooder. Both active on Saturday. On Sunday, chick 1 was very lethargic. She died that afternoon. Monday we got 2 more from the farm they came from.
Chick 2 and now 3 and 4 have been active until today when chick 2 was lethargic. Noticed a bit of pasty butt and cleaned her up. She was pooping again and it seemed watery the first few times. Once dried, you could tell a slight bit of blood. I got her to eat a tiny bit of food mixed w yogurt and then she was sitting in food bowl chowing down before bed.
DH was up at 2:30 and said she didn't look good. She pooped again and it was very watery and you could tell there was blood as well. Then she died.

I have 4 adult ducks, 1 adult chicken and 2 11week old chicks that free range.
I now have chick 3 and 4 that are less than a week old on the patio.
Is this cocci and I should head to TSC tomorrow to get something to treat it?

Is it OK to replace the little blue Cochin I lost this am?

 

[Wyorp Rock]

If you are seeing blood in the poop then you will want to treat for Cocci.
Dosage for Cocci is 1 1/2 teaspoons Corid powder per gallon or 2 teaspoons of 9.6% Corid liquid per gallon
Give for 5-7 days - make sure this is the ONLY water available during that time period. Mix a fresh batch at least once a day.
You can give probiotics or plain yogurt and poultry vitamins when the Corid treatment is finished.

https://www.backyardchickens.com/t/818879/updated-corid-and-amprol-amprolium-dosing
https://www.backyardchickens.com/a/coccidiosis-how-to-treat-it

 

[TLWR]

Thank you.
What level do I treat at for the first link for week old chicks? preventative, moderate outbreak, severe outbreak

 

[Eggcessive]

Whenever there is an outbreak, use the maximum dose no mater what the age is. Cocci is usually not a problem in days old chicks, but more common after 3 weeks old or later. Can you post any pictures of blood in their droppings? Corid is a very safe drug, and whether they have cocci or not, it won't hurt to treat them. They need to drink the medicated water or you will need to give it with a dropper.

 

[TLWR]

The one that had a slight tinge of blood the the droppings died 2 mornings ago. It didn't look like the pics I see of blood in poop for cocci.
I'm still not convinced that's what it was. Chick 1 I think was just never "right" after hatching and was just one of the ones you lose for no apparent reason chicks.
Chick 2 - I don't know. She had pasty butt that day and it was cleaned up and didn't repaste. But droppings I saw after that were squirty/runny and looked like there might be a bit of pinkish tinge to them. I chalked it up to she was plugged up for a little for both the runny and slight color. She did eat and drink after that, but not much and just didn't really perk back up after. I know they can die from pasty butt, but I didn't think it would be that quick. She was clean the day before, so maybe 12 hours plugged up then cleaned and stayed clean. After she died, I realized her wings had been out from her body the day before (when she was pasty, then after - not sure about the day before).

I have corid now, but haven't opened it because I'm just not convinced that's what it was. The others seem fine and are active and exploring, eating like pigs, drinking no problem. So I have it if I do indeed need it, I just don't know that I need it. I hate medicating animals (or myself) when they really don't need it.