The productivity of a population of scavenging village chickens in Sri Lanka has been assessed, and the scavenging feed resource base has been measured and analysed. The laying period lasted 34 +/- 13 days and the batch size was about 20 eggs. The households ate 71% of the egg production. The mean egg weight was 48 g and the mean size of a set of eggs was 9.4. The hatching percentage was 67 +/- 32 and the liveweight at 70 days averaged 313 g with a range of 142 to 492, by which time 65% of the chicks hatched had died. The age at first lay averaged 211 days when the pullets weighed 1,160 g. The broody period lasted from 3 weeks to 4 months depending on whether the hen hatched eggs, and for how long she tended the brood. The laying hens were actively scavenging for most of the daylight hours. The average amount of scavenged feed per household flock per day was 550 g dry weight with a proximate composition of 9.4% crude protein, 9.2% ether extract and 5.4% crude fibre. More than 70% of the feed intake was household refuse (27% cooked rice, 30% coconut residue, 8% broken rice and 36% other scraps). The remainder was from the environment (13% grass shoots, 8% small metazoans and 7% paddy rice). Proximate analyses of crop contents, household refuse and its major components were carried out. Dietary Ca and P levels were low in the village, as were plasma levels of these minerals. On a balanced commercial diet plasma Ca was still lower than that of hybrid commercial chickens. Suggestions are made for improving the productivity of the scavenging system with no requirement for inputs, and with inputs.

1. In 2 experiments the effects of dietary phosphorus on relationships between plasma inorganic phosphorus concentration (Pi), shell and egg production and depletion states were measured in brown laying hens. 2. In a 12-week experiment dietary phosphorus concentrations from conventionally deficient (1.6 g non-phytate-phosphorus (PNP)/kg) to moderate excess (3.9 g PNP/kg) had little effect on egg and shell production, although there was evidence that plasma Pi concentration, when not influenced strongly by shell formation, reflected dietary phosphorus content. 3. Among birds at each dietary phosphorus concentration there was a negative linear relationship between shell weight of early eggs in the sequence and plasma Pi concentration. The relationship was apparently not affected by dietary phosphorus concentration. 4. Continued feeding of the deficient diet to 61 weeks of age did not have effects on body weight, egg and shell production, other than those associated with age, but plasma Pi and bone measurements indicated marginal phosphorus depletion. 5. In another experiment excessive dietary phosphorus (11.9 g PNP/kg) fed in a cross-over design caused small adverse effects on shell production, increased food intake and body weight and increased plasma Pi content, while there was no relationship between shell weight and plasma Pi concentration. 6. The results are consistent with an indirect effect of plasma phosphorus accumulation on shell formation, probably via an inhibitory effect on skeletal calcium release, in addition to any effect of excess dietary phosphorus on intestinal calcium availability. 7. Phosphorus requirement and status in the laying hen are complicated by the failure to recognise the contribution of digestible phytate-phosphorus to the available phosphorus supply.

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COVID-19 has been declared a pandemic since March 2020 and it has been responsible for millions of deaths worldwide. The SARS-CoV-2 causes a spectrum of diseases mainly affecting the respiratory system. It can also complicate other systems causing thromboembolic phenomena and myocardial ischaemia. An entity of hypoxia has been described in these patients which show no clinical signs and symptoms of respiratory distress despite being extremely hypoxic. This is called silent or happy hypoxia. The exact mechanism for this is not known. We report 4 cases which had similar presentations of silent hypoxia but had different course of illness and different outcomes. All 4 patients did not show any signs of respiratory distress, but had oxygen saturation less than 82%. 3 of them needed intensive care unit support for oxygen therapy and subsequently needed noninvasive ventilation. Only one required invasive ventilation. The fourth patient did not require intensive care support. The patient who required invasive ventilation succumbed due to severe COVID pneumonia whereas the other 3 patients were discharged from the hospital. Silent hypoxemia can go undetected in COVID-19 patients particularly in the time of a pandemic. This case series highlights the importance of meticulous clinical examination including oxygen saturation measurements in suspected or confirmed patients with COVID-19. The course of illness can be different in different populations, and this needs further clinical evidence.