Is female can participate in Janaza Salat?
In my relative house they start praying Janaza Salat after the Janaza take out from the house. Is that allowed in Islam? Or this is a kind of Bid'a?
Can women perform salat al janaza
Female can perform salat al-janaza as it's narrated in Sahih Muslim. So it's no bida'h at all if a woman performs this prayer, but a major condition for this is the presence of the corpse of the death person for whom this prayer is performed!
Can women participate at the prayer (in a mosque)
Most scholars say as the rules of the shari'a are valid for women and men and as there are no clear references saying that this worship is only valid for men they shouldn't be prohibited to perform it. But whether they can participate in the prayer if it would mean go out of their houses or not is still a bit unclear and a discussed matter among sunni scholars:
The majority of scholars say women can perform the janazah prayer in congregation in a mosque following the Imam and an other general permission can be derived form the following narration from sahih Muslim.
Some say women shouldn't go to the mosque to perform them and even use expressions like haram or makruh (see for example this fatwa in Arabic) because the say this follows the idea of following the Janaza which is prohibited.
On the other hand we'll have to know that the prayer of funeral is considered a fard kifya which means if some did it this would be sufficient and others wouldn't be regarded as sinners if they don't do.
Beside the funeral prayer we have a similar prayer for those who can not assist the funeral prayer themselves and want to perform this prayer it's called salat al-ghaib (the prayer of the absent), but it has some rulings. So you could do it for a relative who died far away from you, so that you might neither have the possibility to perform the janazah prayer nor pray it at his grave later. And mostly it is done for some people who have been useful for our religion as an-Najashi was and because of his death this prayer was introduced. So still women (and relatives who couldn't pray at the mosque or with the congregation whom prayed the janaza) could perform this prayer at their homes or later.
As those who dislike or prohibit the idea of women praying the salat al-janaza in a mosque use the fact that women preferably should pray at their homes as reason to not let them go and pray at the mosque!
See also this fatwa.
Note: the last few sentences of OP'S question is a bit ambiguous, so I guess that there might be a point which is still missing.
This could be the question: Can women perform the janazah prayer before the "official" prayer in a mosque?
My first referenced fatwa* seem to answer this. As the prayer could be performed once the death person is washed and the corpse has been prepared for burial.
An other point could be is a janzah prayer valid if the death person is not0 (more exactly no more) around?
As usually for praying the janzah their are rules for where to put the death person in front of the Imam. And salat al-ghaib in this case wouldn't be acceptable, as the death person is not far away! So according this fatwa (in Arabic) -where a janazah congregation was held in presence of the wrong death body- the the presence of the death body of the person for whom the janazah is performed is mandatory, if not this isn't a valid prayer. Al-'Assimi an-Najdi العاصمي النجدي said in his comment on zad al-mustanqi' said (speaking about the mandatory conditions to perform salat al-janazah) - (My own translation take it carefully):
وحضور الميت بين يديه، فلا تصح على جنازة محمولة، ولا من وراء جدار.
... The presence of the death person -at the same location- so a janazah prayer on a corpse which has already been moved or carried -out- (to the graveyard) or behind a wall isn't valid.
A 3rd point could also be: Is it acceptable to repeat a janazah prayer?
As if the women performed it the prayer in a mosque or elsewhere would be a repetition. The answer for that it is allowed with details for madhabs, some wouldn't allow it others would say it is allowed, but one shouldn't redo this prayer for the same janazah!
And Allah knows best!
Women are permitted to perform Salat al-Janazah. An instance of women performing Janazah salah can be found in the following hadith:
Ibn Juraij said: "I heard Naji, claim that Ibn 'Umar offered the funeral prayer for nine together. He put the men closer to the Imam and the women closer to the Qiblah, and he placed them (the women) in one row. And the body of Umm Kulthum bint 'Ali the wife of 'Umar bin Al-Khattab, and a son of hers called Zaid were placed together. The Imam that day was Saeed bin Al-As and among the people were Ibn 'Umar, Abu Hurairah, Abu Saeed and Abu Qatadah. The boy was placed closer to the Imam. A man said something objecting to that, so I looked at Ibn 'Abbas, Abu Hurairah, Abu Saeed and Abu Qatadah and said: 'What is this?' They said: 'It is the Sunnah." - (Sunan an-Nasa'i, The Book of Funerals)
I do not fully understand what you mean in the second part of your question. Are you saying that your female relatives pray Janazah at home separately? If so, to the best of my knowledge, this is not Bid'ah (religious innovation). Women are permitted to perform Janazah either at home or at a Masjid.
If there is separate space for women at the Masjid then, women should be allowed to perform Janazah there.
To further evaporate a common misconception, it is not strictly forbidden for females to accompany funeral processions:
Narrated Um 'Atiyya: We were forbidden to accompany funeral processions but not strictly. - (Sahih al-Bukhari, Book of Funerals)
Umm Atiyyah (May Allah be pleased with her) reported: We (womenfolk) were prohibited from accompanying a funeral procession, but we were not compelled (not to do so). - (Riyad as-Salihin, The Book of Visiting the Sick)
I hope this helps.
Women are permitted to participate in funeral prayers. The evidence for that is found in the following hadith.
Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah (ﷺ) said, "Whosoever attends the funeral of a Muslim believing and hoping for the reward from Allah and remains with it until the prayer is offered over it and the burial is completed, he will return with a reward of two Qirat; each Qirat is equivalent to Mount Uhud; and whosoever offers his prayer over it and returns before its burial, he will come back with one Qirat."
This hadith applies to both men and women because it does not specifically refer to men and there is no other evidence that prohibits women from participating in funeral prayers. So, there is nothing wrong with women attending Janaza salats (funeral prayers).
And Allah knows best.
In the name of Allah, the Entirely Merciful, the Especially Merciful
Generally, it is not Mustahab (recommended) for women to participate in the funeral procession (funeral reties), but on the contrary it is Mustahab-al-Mo’akad (emphasized recommended) for men to take part there.