The UK laying hen sector monitors total usage on the basis of bird-days* medicated (daily doses**) as a proportion of the estimated total number of bird-days at risk based on Lion Code census figures.
The Targets Task Force Report published in October 2017 stipulate that total bird/days medicated remains should below 1%, and fluoroquinolone + colistin (HP-CIA) days medicated should remain below 0.05% on an ongoing basis.
For 2018 the egg industry reported in VARSS 2018 that its use was 0.63 daily doses/100 bird-days (or % medication days).
No HP-CIAs were used in 2018. Colistin and 3rd and 4th generation cephalosporins cannot be used under the BEIC Lion Code. In addition, fluoroquinolones cannot be used in day old chicks and any other use can only be where it has been confirmed no other medication is appropriate in order to maintain bird welfare.
Antibiotics are not used routinely in layer flocks.
Vaccines are used to prevent viral diseases, which then prevents any secondary bacterial diseases that might otherwise require antibiotic treatment. The Lion Code requires the vaccination of all birds, destined to produce Lion eggs, against Salmonella.
*A bird-day is the standard denominator used to calculate all proportions, or percentages. For the year, it is the mean daily population of birds in the Lion scheme (including breeding birds and pullets in rear) multiplied by 365.
**A daily dose is a single chicken treated with an antibiotic for one day. Courses of treatment will vary with the clinical need, but are typically 3-5 days. So a flock of 5,000 chickens treated with an antibiotic for 3 days is 15,000 daily doses.