I am an RN, an married to a physician. We use expired drugs a year or two if we are desperate or they look okay, but 10 years expired is pretty old. I wouldn't use it in humans, but for a farm animal it might be okay. If you do use it, look for any sediment or weird color. I always recommend refrigerating injectable drugs. In Plumbs Veterinary Handbook, the dosage for dogs and horses is 25 to 50 mg per Kg (each 2.2 pounds) given every 12 hours intramuscularly. Most cephalosporins are given for 7-10 days. They work against gram positive and gram negative bacteria. I found the following for chicks given subcutaneously below:
!!Birds:
a) Day-Old Turkey Poults: Administer by SC injection in the
neck region of day-old turkey poults at the dosage of 0.17
to 0.5 mg ceftiofur/poult. One mL of the 50 mg/mL reconstituted
solution will treat approximately 100 to 294 day-old
poults.
Day Old Chicks: Administer by SC injection in the neck region
of day-old chicks at the dosage of 0.08 to 0.20 mg ceftiofur/
chick. One mL of the 50 mg/mL reconstituted solution
will treat approximately 250 to 625 day-old chicks. A sterile
26 gauge needle and syringe or properly cleaned automatic
injection machine should be used. (Package Insert; Naxcel®—
Pfizer)
b) Ratites: 10 – 20 mg/kg IM twice daily (Jenson 1998)