It's probably a good reason to avoid lidocaine and other -caine drugs, and use other ones instead. IV injection is the greater risk here rather than topical use. Here are a few articles and treads about the use of -caine medicines in chickens:
Why Not Local Anesthesia? (from exoticpetvet.com)
A bird requiring surgery will usually receive general anesthesia. There are several reasons for this. Many local anesthetic agents, such as lidocaine (usually erroneously called novocaine by lay people) that can numb an area, are toxic at doses that provide numbness! Lidocaine must be precisely dosed, and even so, the dose necessary to provide local anesthesia is greater than the toxic dose, in most cases (in small birds). It can be used in tame, large birds, if necessary. Another problem with using a local anesthetic agent is because restraining a bird awake is often very stressful. Signs of overdose with lidocaine may include excitement initially, seizures, depression, respiratory arrest, cardiovascular collapse and death.