No worries Nancy! I sure do understand the part about being tired. I have to take a lot of little breaks in this heat. I may not consider my chickens pets, but I do enjoy and care for them the best I can. And I'm certainly not above enjoying a fluffy chicky snuggle once in a while either. I like when they purr. Cutest little whirring sound.
I also appreciate you having the forethought to research compassionate care and euthanasia. Most people avoid those ideas when it concerns their pets.
So about the feed. I'll use this bag up, get another 25 pounds (and probably no longer needing to be medicated)and use it up, hopefully by then I've figured they'll be something like 16-20 weeks old by then. Hard to remember how much chicks eat when my last ones were over 20 years ago. If not, I'll buy more chick feed to get them to about 20 weeks or better. I want them on the high protein low calcium feed at least until they start laying.
Anyway, somewhere around 4-6 months old they will be coming into laying age, depending on breed and time of year, supplemental lighting. At POL (point of lay, or of an age to be starting to lay eggs) I'll switch to layer feed. Layer feed has less protein, more calcium, so on. Formulated for laying hens, obviously. Could use grower or flock feed and free-feed oyster shell for calcium. That feed is not medicated. It will partly depend on what's available to me locally at that time. I plan on selling fully half or more of these girls around that time, so getting them started on locally accepted and available quality feed is an important selling point, or would be if I was buying. I'm only keeping a max of 10 hens.
The withdrawal period for each medication given to any meat, dairy, or egg-laying animal (human consumption) is stipulated by the government. A 10 day withdrawal period means you must wait at least 10 days after the last dose given to use the meat/milk/eggs for human consumption. Some meds can be much longer, some even lifetime (the animal or its products must not be consumed EVER), some have no withdrawal period.
Amprolium is the most common coccidiostat (not an antibiotic) used in chicken feed here. I'm pretty sure I'm remembering the withdrawal as being 10 days for both meat and eggs. Doesn't matter for me since, as I said, it'll be months after they ingest it before I'll have eggs to donate, gift, sell, or use myself.
I'm allergic to lots of antibiotics. One of the reasons I raise some of my own food is because of that. If any of these ever get ill to the point of needing oral or injected antibiotics, I will either have to euthanize it or re-home it as a pet. Therefore it behooves me to make darn sure their quarters are impeccably clean and they stay in glowing good health.
I hope that all made sense. I'm sapped from heat and about to find a cool pillow for the night. Enjoy those pretty pet birds!