Hi Zin, welcome to the forum.
For us to advise you regarding the poor condition of the male bird pictured we need more information, for example we need to know it's diet, is the bird on a seed only diet? We need to know things like the age, we need to see photos of the droppings, unfortunately, to me the bird looks to be underweight, but most importantly we need to know how many birds are sleeping in that cage, that cage is not big enough for even one budgie, taking into account the amount of toys, unsuitable perches and that sisal/ straw toy with the red bead on top (which needs to be removed immediately, as does the bell in my opinion) and wooden remains of the seed bars, even one bird has no room to stretch it's wings in the cage, also with regards to the cage, I presume the blanket on top of the cage is used to cover them at night, please find another more suitable blanket to cover them, a fleece blanket is not suitable because the birds (if they haven't already,) will start plucking the fibres and this will cause crop impaction which could lead to an early death.
Thankfully there's a wealth of information on here that will help improve your birds health and wellbeing, please start by following the recommendations above, and then take your time to read the stickies and valuable advice here on the forum. There's always someone on hand if you need further advice, I know my reply sounds a little harsh but as custodians, we are 100% responsible for our captive birds health and welfare.
The purpose of this forum is to promote the BEST PRACTICES in the care of budgies for their optimal Health and Well-Being Locating an Avian Veterinarian
Have you taken your budgie to an Avian Veterinarian for a check-up? That is the very first thing you should do if you suspect it is ill.
Avian Vets have special training to determine the cause of symptoms resulting from illness or trauma.
This is important as "regular" vets will often overlook symptoms that are quickly obvious to an Avian Vet.
When you rely on anyone who has not had training in Avian diagnosis and care, you may be delaying effective treatment.
This can prolong suffering that may be avoidable.
The bird will often require a more intense, prolonged treatment with a poorer chance of full recovery than it would have if you seek prompt professional diagnosis and treatment at the first sign of illness. If there are no Avian Vets near you, please find an Exotic Pet Veterinarian with experience in dealing with small birds.
When you have mixed genders, it is very important to do everything necessary to prevent breeding.
Budgies are much healthier and happier when they are never bred.
Impeckable has given you good information with regard to the housing for your budies.
Please take the time to read through the Site Guidelines, the FAQs, the Budgie Articles and all of the Stickies located at the top of each section of the forum. Additionally, please be sure to read the thread "Posting on the Forums" which is linked below.
Truly, the very BEST advice anyone can offer you is to take the time to read ALL of the stickies throughout the various Talk Budgie forums as well as the Budgie Articles we have posted.
(Stickies are threads “stuck” at the top of each forum sub-section)
These are great resources for Talk Budgie members and have a wealth of reliable information which will assist you to learn the best practices in caring for your budgies for their optimal health and well-being.
It is difficult to understand a budgie's condition just by looking at a photo. Does he have other symptoms? How long have you thought he looked poorly? From the photo he appears to be going through a moult, is this the case? Impeckable is correct regarding diet and cage concerns. Additionally, we need much more information to give you further advice.
FaeryBee has given great advice and has also provided some great resources for you to read. I hope you can get an avian vet appointment soon, since that is the first step whenever budgies are under the weather.
Meanwhile, you’ve come to a great place to learn even more about the best of budgie care practices! Please be sure to have a look around the forums’ many budgie articles and “stickies” to ensure you’re up to date on everything! If you have questions after doing so, please be sure to ask as we’d love to help.