Chicken Manure is another great Natural Fertiliser, although it is much "hotter" than the other two Manures Cow and Sheep.
Chicken Manure has a higher content of Nitrogen, this Nitrogen gives the plant a boost but care needs to be taken regarding the amount used. If you get heavy handed with it on growing plants it can bring on a flush of growth which will ultimately weaken the plant. So a little and often is the rule of thumb here, for an average Tomato plant approx a cup sprinkled onto the ground around the plant and watered in well will suffice, this can be done every three to four weeks to keep the plant "ticking" over nicely. It is great as a pick me up.
Watering it in well is important as if it sits on top of the soil for any length of time it basically bakes and is rendered useless. Working it into the soil will help it break down to a plant available form sooner as well.
It can be bought from your Garden Centre in either loose or pellet form, the pellets being a little less messy.
A great product that is freely available in Aussie is Dynamic Lifter, it is a mixture of Chicken Manure, Blood and Bone and other ferts, again use with care but it will give some great results.
As mentioned in previous entries burying the Manure in the ground for some time to allow it to break down works a treat.
Word of caution don't use Chicken Manure on Potatoes as they will just bolt and not produce any tubers, also be careful with lettuce as again it can encourage them to bolt and not heart up.
Hope this helps,
Be Happy