Usually on fast speed production lines chicken or meat pieces are dossed by a multi-head weigher and the sauces are deposited by the piston fillers.
At few places, I have seen meat with gravy being deposited through a piston filler, but the meat particulate size rarely exceeds 30-35 mm and sauces are pretty thick so the product remains suspended during filling operation. The filling accuracy achieved by this means is +_2 to 5%, depending upon the target weight, product consistency etc.
Riggs Autopack from UK & Makkum in Australia make good piston fillers for this purpose.
http://www.autopack.co.uk/http://www.makum.com/food-packaging-mac ... on-fillers