Broiler Chick Litter Evaluation in Seasonal Trials

The research was carried out in the broiler barn at the Poultry Unit of the Department of Animal Science, Faculty of Agriculture, Gaziosmanpaşa University.
The animal material of the experiment consisted of mixed-sex broiler chicks (Ross 308), which were obtained from a private commercial breeder. On the day of arrival corresponding to the start of the trials, the day-old chicks were weighed to ensure that the average chick weight was similar in the replicate pens. The wing-tagged chicks were distributed to 15 pens of 2 × 2 m in size (5 litter treatments × 3 replicates) according to the study plan. 50 birds with an equivalent of 12.5 birds/m² were allotted to each replicate pen. There were 150 chicks in each litter treatment, 750 in each trial (summer; 09 July – 19 August and winter; 26 December – 05 February), and a total of 1500 chicks. The number of males and females in each litter treatment replicate pen at the beginning and at the end of the experiment (42 days of age) both in the winter and summer season trials are indicated in Supplementary Table 1.
The litter treatments in each trial involved wood shavings (WS), acidic pumice (AP), and basic pumice (BP), and the mixtures: wood shavings + acidic pumice (WSAP), and wood shavings + basic pumice (WSBP) in a ratio of 1:1. The litter treatments in each trial are shown in Fig. 1.
Fig. 1

Experimental litter treatments (A: Wood shavings, B: Acidic pumice stone, C: Basic pumice stone, D: 50% wood shaving + 50% acidic pumice stone, E: 50% wood shaving + 50% basic pumice stone)

The average litter thickness for all litter groups was 5 cm. To prepare mixtures consisting of different litter materials, each replicate pen of 4 m² was divided into two equal parts. Thereafter, each litter material was laid in the corresponding section until it was 5 cm deep and consequently, mixed thoroughly.
Standard concentrate feeds purchased from a commercial enterprise were used as feed material throughout the trial. Chick starter feed: between 0 and 14 days (d), broiler grower feed: between 15 and 35 d, and broiler finisher feed: between 36 and 42 d. The general composition of the feeds used in the seasonal trials is given in Table 1.
Table 1

General nutrient composition of feeds used in the summer and winter trials

Nutrient composition	Summer			Winter
	Chick starter feed	Broiler grower feed	Broiler finisher feed	Chick starter feed	Broiler grower feed	Broiler finisher feed
Crude protein, %	22	20	18	23	21	18
Crude cellulose, %	5	5	5	4	4	4
Crude ash, %	9	9	9	8	8	8
Calcium, %	1-1.5	0.8–1.2	0.9–1.5	1-1.5	0.8–1.2	0.9–1.5
Phosphorus, %	0.50	0.40	0.40	0.5	0.45	0.40
Lysine, %	1.2	1.1	1.0	1.3	1.1	1.0
Methionine, %	0.6	0.5	0.4	0.6	0.5	0.4
Metabolic energy, Kcal/Kg	2900	3050	3200	3050	3150	3200

The study barn was naturally ventilated and had tube feeders and automatic hanging drinkers. Electric heaters ensured the heating of the barn. From the first until the final day (42 d) in both trials, the temperature and humidity values inside the barn were recorded per hour using data loggers hanging at the back level of the birds. The weekly ambient temperature and humidity in the two trials per treatment group are shown in Supplementary Tables 2 and 3, respectively.
From the day of the arrival of chicks to the final day of the trials, a photoperiod (light to dark, L:D) of 24 L:0D was ensured.