Poultry farming is a profitable business but is facing serious ammonia environment particularly during winter season when ventilation frequency is reduced to maintain the shed's temperature. Urease producing bacteria in droppings are main cause of emitting ammonia in the sheds. The ammonia poultry environment is inducing reduced weight gain, immuno-suppression, enhanced susceptibility to respiratory pathogens, etc. Aqueous and alcoholic extracts of 14 local herbs (Aloe Vera, Azadirachta indica, Allium sativum, Calotropis procera, Cannabis sativa, Carum capticum, Eucalyptus camaldulensis, Lantana camara, Mangifera indica, Mentha piperita, Nigella sativa, Opuntia ficus indica, Piper nigrum and Zingiber officinalis) and four commercial herbal products (Mentofin, Suduri, Safi, Yucca) were evaluated for their in-vitro antibacterial activity against Proteus mirabilis by serial dilution method. It was observed that with reference to rise in pH, Ammonia concentration and urease activity in aqueous and alcoholic extracts of Allium sativum (pH: 8.5560, 8.8480, Ammonia:4.42, 3.52 µg/mL, Urease: 0.009, 0.007 U/mL respectively) had shown best results as compared to control positive (pH: 9.03, Ammonia: 6.7µg/mL, Urease: 0.013 U/mL). Alcoholic extracts of Mangifera indica (8.8820, 5.42µg/mL, 0.010 IU/mL), Mentha piperita (8.8880, 4µg/mL, 0.008 U/mL) Carum capticum (8.9540, 4.84µg/mL, 0.009 U/mL) and aqueous extract of Opuntia ficus indica (8.8100, 5.22µg/mL, 0.010 U/mL) had weak activity against P. mirabilis. Both aqueous and alcoholic extracts of Eucalyptus camaldulensis (pH: 8.91, 8.96, Ammonia: 5.16, 5.06 µg/mL, Urease: 0.01, 0.01 U/mL) has weak inhibitory effect. All commercial products had shown strong antibacterial activity (pH: 4.8-6.8, Ammonia: 0µg/mL, Urease: 0 U/mL). Results of remaining herbal extracts were not significantly different (p<0.05) from positive control. It was concluded that all herbal products had strong antibacterial activity against P. mirabilis. Mentofin had shown best results with optimum inhibitory concentration (1/1000 mL). Alcoholic extracts of few herbs had shown weak bactericidal activity. These herbs might give better results in-vivo.