Fig. 1
Sampling scheme for the longitudinal study of extraintestinal Escherichia coli in pullets and layers. Each box represents an individual sampling event and includes the following information: farm/flock identification (rearing farms are indicated as RI - RVI and layer flocks are designated with letter “L” along with flock number/corresponding rearing farm number) – age of birds during sampling (weeks) – number of E. coli isolates in parenthesis