Effect of Choice Feeding on Footpad Dermatitis and Tonic Immobility in Broiler Chickens

Nowadays, genetic improvements have provided chickens with faster growth in lower production periods. In this situation skeletal abnormalities and stress are the negative consequences of the chickens’ modifications (Robinson et al., 1992). On the other hand, feeding planners have to exert several feeding programs due to the alternating changes of birds’ requirements and also their welfare situation during the time (Shariatmadari, 2012). Therefore, with the ever increasing concern of consumers for food quality and animal welfare, it is necessary to use applicable welfare measurements. Choice feeding is a program which let chickens to feed base on their needs and so they can choice between diets offered to them (Munt et al., 1995). Some countries still using footpad scoring to evaluate the welfare situations of broiler chickens (Allain et al., 2009). Tonic immobility also is an indicator of chicken fearfulness (Jones and Faure, 1980). Therefore, the objective of the present experiment was to evaluate the impact of choice feeding with diets varied in energy and protein on footpad dermatitis and tonic immobility of chickens.

In this experiment, total of 195 day-old broiler chicks (Ross 308) were randomly allotted to 3 treatments and 5 replicates of 13 chickens in completely randomized design. The diets varied in energy (E+ = 3210 kcal/kg and E− = 2790 kcal/kg) and protein (P+ = 25.14 % CP and P− = 16.76 % CP) contents. Chickens were choice fed by dietary treatments included of control group (ME: 3000 kcal/kg, CP: 20.95 %) or either intermittently fed by HL (choice feeding of high energy diet and low protein diet followed by high energy diet and high protein diet); and LH (Choice feeding of low energy diet and high protein diet followed by high energy diet and high protein diet) in 48 h cycles, during growing period since day 8 until 28 of age. Pad dermatitis was evaluated by using a 4-point scale from 0 to 3 in which 0 shows no sign of damage and 3 is for extended burn and inflammation of 8 chickens per pen on day 35 of age (Sørensen et al., 1999). Tonic immobility also was tested on 3 male and 3 female chickens on day 39 from each pen considering Campo and Redondo (1996) method.

The results suggested that chickens fed by LH group had significantly greater values for footpad dermatitis scores (P<0.05) which might be attributed to the higher protein fed by chickens in this group and their subsequent excretion of ammonia to the litter which negatively compromise the footpad of chickens (Sirri et al., 2012). However LH group insignificantly showed the lower time duration in tonic immobility compared to HL but was not significantly changed compared to control group which might shows that choice feeding had no negative effect on chicken’s fearfulness.

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