How long can a sick chicken go without eating or drinking?

[Jculpepper]

Info/Background:
My girls where born this year in March. I have RIR, Black sexlinks and Bard rocks. I have 12 total! On Wednesday this week I noticed one of my girls (a Black Sexlink) started weezing and coughing. I went to the feed store and they told me to give the flock poltry cell and Duramycin - 10 (tetracycline). The antibiotic is mixed into their water once a day for 6 days. This was started on Wed. The chicken that was originally sick was doing great the next day however, Friday morning I noticed a different hen (a bard rock) acting very tired and not interested in doing anything. By Friday afternoon there where 2 Bards acting like this Everyone else is free ranging and they are just sleeping. 2 other chickens (A different bard and a different Black) are free ranging but one eye is closed. The whole flock sounds/looks snotty, but 8 are still acting normal. I did separate 4 the bad ones.
On Sat morning all 4 that were starting to look bad looked worse, so I went out and got Tylan-50 and began shots ½ cc 2x a day for all 12 girls. First shot was Sat afternoon. The 4 did not eat or drink Sat.
On Sunday the 4 still were showing no improvement L I mixed their dry pellet food with water and plain yogart and got all but one to eat some and drink. The same 4 are still looking bad today. We do not have a vet that will see chickens where I live, but I was able to bring a fecal sample to my dogs vet and there are no worms or coccidia. Crops are empty.
How long can they go on like this?

 

[QueenMisha]

Most birds can go about 3-4 days without drinking and a week or so without eating. But you'll see a lot of deterioration during these periods prior to death. And mind that these are estimates and actual times will vary by individual.

It sounds like your flock probably has a contagious respiratory disease. See if you can find an avian or exotics vet anywhere within a reasonable drive - it's very critical that you have blood tests done to to determine what the exact issue is. There are literally dozens of different respiratory diseases, many of which present with identical symptoms but cannot be treated with the same medications. And absolutely check out your environment to be sure that's not the issue! Is it possible your birds somehow got to moldy feed? What kind of bedding do you use and is it being kept clean enough?

I've had quite a bit of success using a NutriDrench/ACV combo in my birds water (1 week out of each month or two) to treat Mycoplasma S. and G. I have no idea how it will interact with other diseases, but it sure can't harm them. On that note, being as Myco is the most common respiratory disease, if you absolutely can't find anybody to blood test your birds anywhere, then go online and order some Denagard. QC Supply is cheapest, 1 liter of 12.5% solution for $45 + shipping. It blows Galli/Duramycin out of the water in terms of effectiveness, and has saved the lives of many a bird in my flock. And while it is specifically recommended for use in Myco infections, it's not going to cause any adverse reactions if your flock is infected with something else.