Soft Ticks. Soft ticks feed primarily on the blood of birds. They are typically nightly feeders and return to protected locations to hide during the day. One of the more damaging species is the fowl tick (Argas periscus), which is one of the more important worldwide poultry pests. Nymphs and adults of this tick are very active at night. It is not unusual to see large numbers of these ticks crawling up the roosts, filling with blood and before daybreak leaving for their daytime hiding places. The larval stage, once attached to the host, remains to engorge with blood for several days. Under favorable conditions the entire life cycle may be complete in as little as 30 days. In the absence of an available host this can be extended to several months.
A soft tick (Argas persicus) lacks the scutum and capitulum not visible from a dorsal angle. Image courtesy of Matt Pound, ARS, Bugwood.
Heavy infestations of these ticks may result in a rundown condition, loss of weight and reduced egg production. Secondary infections may occur which can result in the death of the animals. Fowl ticks will attack humans, especially in the absence of their preferred hosts.
Here's a link to external parasites in poultry with pics, scroll down to the fowl tick. Apparently they are difficult to get rid of and will require multiple pesticide treatments in coops over time. http://edis.ifas.ufl.edu/ig140
The OP's location is listed as Pakistan... I had to double check when I saw this thread, too, because I sure don't want to add this critter to the ones I have to worry about!