Ammonia emissions from laying hen facilities may be reduced via pre- and/or post-excretion pathways. Our labscale tests to date have shown the following: a) reducing surface to volume ratio of manure stacks leads to reduced ammonia emission; b) an experimental diet (Ecocal) for W36 laying hens showed a 41% reduction in manure ammonia emission, as compared to the control diet, over a 14-d manure storage period; c) topical application of zeolite to laying hen manure at 2.5 to 5% (by weight) reduced ammonia emission by as much as 66-91% within one day of application; d) topical application of alum to layer manure at 0.5 kg/m2 (0.1 lb/ft2) reduced ammonia emission by 63- 90% during seven days after the application, and emission reduction rate for application rate of 1.0 or 1.5 kg/m2 (0.2 and 0.3 lb/ft2) was at about 93% during the 7-d postapplication period. Cost effectiveness and practicality of each mitigation option remain to be examined.