I don't think this is true. As I understand it, any FDA human or veterinary drugs can be used as long as it's not on the banned list and the veterinarian follows a set of complicated rules.
https://www.avma.org/KB/Resources/FAQs/Pages/ELDU-and-AMDUCA-FAQs.aspx
No, actually that is true. Even if the veterinary prescribes the med, if it is still FDA "off label" for layers (and note there are no VFD meds listed for layers on the FDA drug listing...which is what you have to go by), then technically the bird can no longer be in the human food chain.
It is a government created conundrum. (Big surprise).
You are expected to treat ailing animals. If you treat said animal with meds that are not labeled for use in your species and purpose, in other words off label and FDA non-approved for use in that animal/use, then the animal must be removed from the food chain.
There are more meds available for meat broilers, OTC and VFD, as those are more problematic for the industry and thus meds are still regularly used (as lobbied by the industry).
However, the layer industry has solved the health issue by simply rotating buildings/fields and flocks...culling anything more than 2 years of age....due to the natural reduction in laying of hens over 2 years. So, there is no interest in expending dollars for the animals, since with careful management most birds under 2 are relatively parasite and disease free, therefore meds have not been lobbied to remain in place.
Organic farmers are prevented from meds/drugs to maintain organic standing, however, they are expected to treat the animal then remove them from the food chain. As you can imagine, the temptation is simply to remove the animal without treating as it is expensive to treat and then keep an animal that is useless for the operation.
BYC owners have recommendations as per FARAD, but these recommendations are slowly being more restricted as products are removed from shelves.
FDA currently is viewing backyard chickens under "pet" classification, but there is more pressure to place them in "livestock" classification because of the risk of their products (meat/eggs) making it to human consumption beyond the family.
LofMc
http://www.usfarad.org/treating-layers.html
per FARAD: "Discerning which medications are approved for use in laying hens can be confusing. In order to determine if a medication is approved for use: 1. check that the medication is labelled for "chickens, all classes." The label may even state for use in layers or laying hens. 2. Determine that the label does not exclude "Laying hens" 3. Determine that a tolerance in eggs exists for the drug. This may be done by checking the
VetGram or
FDA Animal Drugs websites. For more on tolerances see "Rules & Regulations."
Here is the current VetGram...note any antibiotics are excluded from layers.
http://www.farad.org/vetgram/egglayers.asp
So if you have laying hens, pretty much all that you can legally give them, right now, per FDA approval, is amprolium (Corid) or bacitracin. I did just note under the VetGram that Hygromycin-8/Hygromycin B is on the all class approved list pending January 18th, 3 day withdrawal...no mention of layer exclusion.
That has been off the market without approval, but it looks like it may be coming back on the market. (I will be buying some as soon as it hits the markets).
Remember, these rules change regularly. It can be a real nightmare for the farmer to keep up with them.
And remember, for the BYC owner, do what is right for your family. If the bird is for family use, you can make your own rules according to what you feel is safe.
If you sell or give away eggs, I personally feel it is wise to follow FDA rules or FARAD suggested pull times.
And yes, many BYC people can go to a vet who will prescribe long-standing effective drugs, that are off-label, and then wait a pull time and do what they want with the eggs. But "technically" they are not supposed to do so.
There are no egg police, as of yet, for the little guy. It is only if your eggs were ever tested that you would come under FDA reg liability and penalty if residues were found.
So many use a pull time of 30 days to be certain there is no possibility of any residue being found in a sold or gifted egg. (That usually means the family eats the eggs, or the family dog, depending upon how you feel, and you wait to sell or give away eggs).
LofMc