Chicken Dinosaurs

Yulong - An Oviraptorid Dinosaur of the Cretaceous 

Yulong mini was a dinosaur of the Cretaceous. The systematic paleontology of it is:

Dinosauria Owen 1842
Saurischia Seeley 1887
Theropoda Marsh 1881
Oviraptoridae Barsbold 1976
Yulong Lu et al. 2013
Yulong mini et al. 2013

Junchang Lu, Philip J. Currie, Li Xu, Xingliao Zhang, Hanyong Pu, and Songhai Jia wrote an article titled Chicken-sized oviraptorid dinosaurs from central China and their phylogenetic implications. It was published in 2013 in Naturwissenschaften. This quote from the abstract says:

Oviraptorids are a group of specialized non-avian theropod dinosaurs that were generally one to 8 m in body length. New specimens of baby oviraptorids from the Late Cretaceous of Henan Province are some of the smallest individuals known. They include diagnostic characters such as the relative position of the antorbital fenestra and the external naris, distinct opening in the premaxilla anteroventral to the external naris, antorbital fossa bordered by premaxilla posterodorsally, lacrimal process of premaxilla does not contract the anterodorsal process of the lacrimal, parietal almost as long as frontal; in dorsal view, posterior margin forms a straight line between the postzygapophyses in each of the fourth and fifth cervicals; femur longer than ilium. They also elucidate the ontogenetic processes of oviraptors, including fusion of cranial elements and changes in relative body proportions. Hind limb proportions are constant in oviraptorids, regardless of absolute body size or ontogenetic stage. This suggests a sedentary lifestyle that did not involve the pursuits of similar-sized prey. The functional implications for bite force and therefore dietary preferences are better understood through the study of such small animals. The comparison of the measurements of 115 skeletons indicates that oviraptorids maintain their hind limb proportions regardless of ontogenetic stage at absolute size, which is a pattern seen more commonly in herbivores than in carnivores. This may weakly support the hypothesis that oviraptorids are herbivores rather than active carnivores.

The authors mention that most of the Yinglong specimens are 0.25-1.64 m. (0.82-1.64 ft.) long. The holotype (4GM 41HIII-0107) is an extremely well preserved skeleton.