The information on the Shililah site is correct concerning the various different withdrawal times for different ivomec products (ivomec is the brand name for different products) ... it is very difficult for the layman to ascertain (outside of the ivomec Eprinex product ) which of those are associated with the longer withdrawal times. (and yes I have run across withdrawal info on poultry from other countries where ivermectin (1%) and the "Eprinex "
are allowed and commonly used for poultry and birds > here in Holland you can buy ivermectin in pre-measured "spot-on" pipets for the size of a canary up to the size for pheasants.)
See here (veternarian advice for 4-H from Ohio State Univ.)
http://www.oardc.ohio-state.edu/poultry/NovWingRap.htm
"Question: The scales of my chickens feet do not lay flat. Is this caused by scaly-leg mites?
Answer: Scaly-leg mites are a species of mites known as Knemidocoptes mutans. These mites burrow under the scales of the chickens feet to eventually cause the scales to be lifted. In severe infestations, there can be a loss of the digits (toes). Treatment with ivermectin has been reported to reduce the severity of this infection in the flock. Your local veterinarian can assist you in developing a treatment plan for your bird(s). In addition, applying a petroleum-based jelly to the affected shanks and legs in an early stage of the infestation can assist in having the scales return to its original state. If left untreated, the infestation can progress and the scales will remain up turned or in severe cases, the toes can fall off. Hence, if you suspect a case of scaly-leg mites, it is important to diagnose and treat the bird(s) quickly.
Teresa Y. nonsense, DVM, PhD, Dipl. ACPV is a Professor and Extension Poultry Veterinarian in the Department of Veterinary Preventive Medicine. She is a board-certified poultry veterinarian and is also the Director of the Avian Disease Investigation Laboratory at The Ohio State University. She welcomes your questions and invites you to contact her at the Department of Veterinary Preventive Medicine, The Ohio State University, 1920 Coffey Road, Columbus, OH 43210 or contact her through this website at
www.oardc.ohio-state.edu/poultry/"
Because there are various formulations of avermectins/ivermectin products and because the use of the specific 1% ivermectin or ivomec-Eprinex is so widely known within the (hobby/non-farm) poultry circuit and bird fancier world and the info from countries using the same ( and I have never seen a withdrawal length of more than three weeks for either of these two specific products though it does vary frm country to country) I would think the main concern to be if you are using your birds for meat purposes or your customers or yourself is concerned about the sources of your food being organic or you have (health) sensitivity issues.
If your birds are primarily pets and you are concerned about the eggs then you have nothing to worry about IMHO if you observe a three week withdrawal time.