s ▁and ▁mis con ception s ▁about ▁ch ick ens ▁and ▁their ▁behavior ▁are ▁central ▁to ▁issues ▁surrounding ▁passage ▁of ▁city ▁ordin ances ▁and ▁reg ulations ▁necessary ▁for ▁the ▁keeping ▁of ▁urban ▁ch ick ens : ▁ ▁Health ▁Bird ▁flu ▁and ▁sal mon ella ▁are ▁the ▁two ▁biggest ▁concerns ▁to ▁human ▁health . ▁The ▁risk ▁for ▁catch ing ▁bird ▁flu ▁is ▁low , ▁according ▁to ▁Mark ▁Sl if ka , ▁Ph . ▁D . ▁In fect ious ▁D ise ase ▁Ex pert ▁with ▁Oregon ▁Health ▁& ▁Science ▁University ▁in ▁Port land , ▁OR . ▁He ▁states ▁this ▁is ▁especially ▁true ▁if ▁the ▁h ens ▁are ▁kept ▁in ▁a ▁closed ▁environment , ▁since ▁they ▁wouldn ' t ▁be ▁exposed ▁to ▁other ▁birds . ▁ ▁Sal mon ella ▁is ▁mostly ▁associated ▁with ▁under - co oked ▁ch icken ▁meat . ▁People ▁who ▁have ▁weak ▁imm une ▁systems , ▁such ▁as ▁the ▁elder ly , ▁young ▁children , ▁and ▁those ▁with ▁various ▁medical ▁conditions , ▁are ▁most ▁at ▁risk . ▁Pro per ▁san itation ▁and ▁cook ing ▁practices ▁less en ▁the ▁threat ▁of ▁contract ing ▁sal mon ell osis . ▁Ch icken ▁f ec es ▁can ▁also ▁inf ect ▁water ▁sources ▁with ▁Sal mon ella . ▁If ▁ch ick ens ▁are ▁kept ▁an ▁ade qu ate ▁distance ▁from ▁water ▁sources , ▁the ▁risk ▁of ▁cont amin ated ▁water ▁sources ▁from ▁ch icken ▁f ec es ▁is ▁significantly ▁reduced . ▁Av ian ▁influen za , ▁commonly ▁referred ▁to ▁as ▁" bird ▁flu " ▁is ▁spread ▁through ▁contact