(a)(i) Meaning of incubation in poultry production: This is the process of providing optimum conditions of temperature, air flow and atmospheric humidity for fertilized eggs to hatch into chicks either by natural or artificial means.
(ii) Advantages and disadvantages of natural incubation:
Advantages: Labour requirement is low. It is cheap. No risk of power failure. Maintenance cost is low. Does not require special skill/expertise. Favourable conditions for hatching are naturally provided.
Disadvantages: Unpredictable number of eggs are hatched. Process cannot be programmed. There is risk of predators/ parasites. Not suitable for commercial production. Low hatchability of eggs. Eggs are often exposed to adverse weather conditions. Few eggs are usually layed for incubation. Possibility of abandonment of i eggs is high. Pecking and sucking of the eggs by the hen.
(b) Factors that affect pasture establishment in West Africa:- Quality of pasture seed. - Water/ Rainfall. - Temperature. - Light. - Soil physical properties. - Pest. - Diseases/pathogens. - Competition for soil nutrients. - Prevalence of weeds.
(c) Causal organism and Symptoms of Brucellosis and Newcastle Diseases

S/N	Disease	Causal Organism	Symptoms
1	Brucellosis	Bacterium (Brucellaabortus or BrucellaSpp,)	(i) Premature abortion (ii) Still births mature abortion (iii) Retained placenta (iv) Infertility in male animals. (v) Low milk yields. (vi) Death of calf (vii) Inflammation of the uterus leading to sterility
2	Newcasele	Virus	(i)Drop in feed intake/Loss of appetite. (ii) Severe respiratory difficulties. (iii) Neck twisting/torticollis (iv) Sneezing and coughing. (v) Paralysis of legs/wings. (vi) Decline in egg production.(vii) Laying of soft shelled eggs. (viii) Greenish diarrhoea. (ix) Loss of weight. (x) Foul smelling feaces. (xi) Droopiness. (xii) High mortality