Table 1.

Model parameters and baseline values.

Expression	Description	Value
rCj	Growth rate for Campylobacter strain j.	0.3009
r2	Growth rate for other bacteria (B).	0.1407
α1	Campylobacter competition coefficient.	0.9744
α2	Other bacteria competition coefficient.	1
γCj	Rate of inhibition by host defense peptides (P) on Campylobacter strain j.	0.6358
ξj	Rate of host defense peptide growth in response to Campylobacter strain j.	0.7411
b	Rate of broiler shedding Campylobacter into the environment, Ej.	10
Ω	Total environmental carrying capacity of Campylobacter.	200, 000*
dCj	Death rate of Campylobacter strain j.	0.0185
d2	Death rate of other bacteria.	0.0212
d3	Decay rate of host defense peptides.	0.0463
d4	Decay rate of maternal antibodies.	0.0046
d5	Death rate of Campylobacter in the environment.	0.05
βCj	Rate of inhibition by other bacteria on Campylobacter strain j.	0.0276
σCj	Rate of inhibition by maternal antibodies on Campylobacter strain j.	0.0661
ηCj	Scaling factor applied to stochastic Campylobacter growth in the gut.	0.01
ηBCj	Scaling factor applied to stochastic Campylobacter inhibition by other competing bacteria.	0.0847
η2	Scaling factor applied to stochastic competing bacteria (B) growth.	0.01
η3	Scaling factor applied to stochastic host defense peptide (P) growth.	0.01
η4	Scaling factor applied to stochastic maternal antibody (M) decay.	0.01
η5	Scaling factor applied to stochastic Campylobacter growth in the environment.	0.01

Descriptions for all parameter values appearing in the final stochastic model, Equations (14–18). Baseline values are given, used for model validation and simulation case studies. Values were calculated by using simulated annealing to identify a parameter set that best fits the experimental data of Achen et al. (1998) (Figure 2). See Appendix S2 in Supplementary Material for an explanation of simulated annealing.

^*Ω value is dependent on the experiment specifics for model validation, but flock case studies consider a flock of 400 chickens, and an Ω value of 200,000.